[release-notes] #79 Changelog in release notes separated by assigned labels
[release-notes] #79 Add support for custom header for Other improvements
[release-notes] #79 Minor improvements

 - Better support for nested sub lists in Markdown
 - Fix incompatibility with Java 7
 - Remove displaying category with 0 changes
 - Enhance displaying list with no changes at all
 - Support for "new feature" label
Automatically generate IDEA metadata for buildSrc
Added very simple validation for missing github token.
Simplified the code
Fixed problem with binary equal calculation

Ensured the marker file is deleted before each run so that 'clean build' is not required for correct behavior.
Pushed creation of release notes builder to runtime.
Rework in the automation.

Made it possible to run binary comparison task without providing the github token. Rename job and refactoring in the release notes automation machinery.
Added some TODOs.
Added utility class for argument validation.
Added pom comparison for detecting if the release is needed.
Fixes to pom comparison.
Fixed line endings
Started comparing source jar files correctly
Final fixes to the release procedure.

Now Mockito automation should correctly detect whether the release is actually needed.