* vendor Azure Go SDK (#210)

* vendor the Azure Go SDK and dependencies

* add initial Azure DNS provider implementation (#210)

* add 'azure' value to 'provider' command line option
* add 'azure-config-file' command line option
* add 'azure-resource-group' command line option
* implement initial Azure DNS provider

note: azure provider is not yet fully implemented (does not query for existing
records).

tests and documentation are forthcoming.

* add a tutorial for the Azure provider (#210)

* add tutorial for using ExternalDNS with Azure DNS

* finish implementation of Azure DNS provider (#210)

* implement the Records method for the Azure DNS provider

* refactor Azure API interface for future tests (#210)

* make Azure provider use an interface for future unit tests

* add unit tests for the Azure provider (#210)

* test retrieving Azure DNS records.
* test updating and deleting Azure DNS records.
* test dry run for the Azure provider (i.e. noop).

* ref(source): use testify with mocks in test code

* fix: re-introduce NewMockSource for convenience

* fix: avoid circular dependency

* ref: increase usage of testify

* chore: vendor testify as a dependency

* fix(*): cleanup testify expectations

* Expose inmemory provider to cli

So we can test `--source fake` without needing to touch AWS/Google.

* Add FakeSource

`external-dns --provider inmemory --source fake --dry-run --once`

OR

`external-dns --provider aws --source fake --fqdn-template <hostname suffix> --dry-run --once`

NB: `--fqdn-template` because otherwise we'll default to creating, e.g.,
`abcd.example.com`, which `--provider aws` filters out because you
likely don't have a Zone for `example.com.`  Could also be resolved by
removing the need to use a real provider; the inmemory provider,
perhaps, though it's not entirely hooked up.

Closes kubernetes-incubator/external-dns#22

* Style feedback from Travis CI

* Improve optionality of kubernetes client

* ref(sources): refactor source registration and lookup to be lazy.

* Revert "ref: refactor source registration/lookup to be lazily initialized"

* chore: add instrumented HTTP client library

* feat: add client-side metrics to outgoing HTTP clients

Closes #206

Closes: #47

* chore: update and vendor all dependencies

* chore: don't forget custom import repo-infra

* reactor inmemoy provider

* add inmemoryclient to logically split functions

* implement apply changes

* fix all tests

* chore: use bogus value for zone to ensure it's ignored

* chore: use bogus value for zone to ensure it's ignored (2)

* adjust docs before the v0.3.0 release

* minor fixes

* docs: add missing dot

* docs: add missing dot

* docs: drop line

* docs: drop another line

* adjust documentation

* update main readme

* checkbox for releases, add --txt-owner-id flag in description

* docs: minor weird character fixes [ci skip]

* feat: add and use a deduplicating source

* chore: add log entry when endpoint was deduplicated

* feat(config): change defaults, switch flag processing to kingpin

* chore: vendor kingpin as a dependency

* feat(config): auto-detect cluster config from the environment

* chore: clean up definition of flags

* chore: sanitize flags even further

* chore: update changelog with latest flags changes

* fix(aws): fix messed up test name

* minor improvements to logging

* chore(*): change log.Infoln to log.Info

* fix: fix incorrect example code

Bug in question: https://github.com/kubernetes-incubator/external-dns/issues/154

This is fixed in 0.2.1

* feat(google): auto-detect and multiple zone support

* chore: run gofmt with the simplified command

* fix: pass desired domain to google provider

* feat(google): correctly auto-detect records for sub-zones

* chore: update changelog with support for multiple zones in google

* fix(google): don't append traling dot to TXT records

* ref(provider): extract hostname sanitization to general provider

* continue on controller loop error

* add logging in source

* use formatter on logChanges for endpoints

* fix log messages, log skipped records

* add logging in aws, uppercase the rest

* respect google dry run policy

* add ing/svc namespace/name on logging

* fix error logging on template failure

* fix bugs, propagate template error

* log if nothing is being updated, debug log skipped endpoints

* change zone-not-found logging order

* feat(service): enhance compatibility, process molecule services

* ref(service): simplify label detection for molecule servics

* change owner key in txt records

* ref(registry): change semicolon to comma

* add --fqdn-template

* add missing ,

* gofmt

* no endpoint creation on empty fqdntemplate

* improve test coverage

* gofmt simple on service_test.go and ingress_test.go

* import package order changed

* gofmt

* refactor to generate template in the source init

* refactor for err handling

* fix service tests

* fix wrong check, check for priorities, mate > template

* fix tests, check for controller annotation in the right place

* add to changelog

* add flag description, improve testing, reorganize imports

* review changes: log the error, use text/template, change func interface

* feat(aws): support multiple hosted zones and automatic lookup

* chore: run gofmt with the simplified command

* fix(aws): add missing method from google provider

* fix: remove superflous parameter from google provider

* feat: make domain configurable via flag

* fix(aws): remove unused constant

* fix(aws): don't log actions that were filtered out

* feat(aws): detect best possible zone to put dns entries in

* fix(aws): log error instead of failing if a change batch fails

* chore: update changelog with support for multiple zones

* feat(aws): support for creating DNS records with ALIAS type

* fix(aws): increase code coverage by listing ALIAS records

* chore: update changelog with support for ALIAS records

* ref(aws): generalize naming of ELB to load balancer

* ref(google): remove superflous check for non-existing record

* fix(aws): return the correctly typed alias record

* feat(plan): allow plans to be parameterized via policies

* fix(controller): set a policy in the controller tests

* chore: allow go tip to fail

* chore: update changelog to include policies

* fix(plan): store a pointer to changes

* fix(controller): don't get address of a pointer

* kickoff txt registry

* fix inmemory dns provider to include recordtype info for validation

* Merge master

* fix ununsed variable in inmemory provider

* add tests for records

* add test for no prefix name formatter

* implement apply changes with tests

* add flag to enable txt registry

* add txt registry to main

* improve sort testing

* filter out non-owned records

* NewEndpoint(...) requires record type

* use newendpoint in aws_test, fix tests

* change suitable type implementation

* fix the test for compatibility component

* change inmemory provider to include recordtype and use suitable type

* fix comments, CNAME should target hostname

* name mapper do not use pointer on struct

* txt prefix - just concatenate, remove spew, fix txt record label

* allow TXT records as result from dns provider

* add changelog

* fix tests

* TXT records need to be enclosed in double quotes