GitLab

* Make suitableType() be Endpoint method

With this change it becomes possible to work with endpoint
of empty type in packages other than "provider". Also
it seems logical for a smart property getter without side effects
to be a method rather than a function in different package

* Make plan computation work correctly with multi-target domains

* fix drawing

* drop comments

* fix boilerplate header

* fix comment

* fix the bug with empty map

* rework registry to support random lables

*  serialize->serializeLabel function rename

* golint for err variable naming

* add additional test

* add tests for current case where one resource can generate multiple endpoints

* make labels have its own type, add serialization as a method

* add comment for exported error

* use greater rather than not equal zero

* update changelog