Issue #371 Implemented RtCollaborators methods and unit Tests.
PDD definition fix in RtCollaborators.
RtCollaborators constructor made non public.
ReleaseAsset.Smart Attributes fetchs and Unit Tests. Issue #505
ReleaseAsset.Smart Override methods implemented
ReleaseAsset.Smart updates fields
ReleaseAsset.Smart and tests implemented Issue #505
Merge branch 'master' of https://github.com/jcabi/jcabi-github into 505
ReleaseAsset.Smart Tests fix. One test per method in Smart.  Issue #505
Merge branch 'master' of https://github.com/jcabi/jcabi-github into 371
issue_471
Merge pull request #555 from jac1013/issue_471

#555: pull request issue_471
Merge pull request #542 from andrescandal/505

#542: pull request Implemented ReleaseAsset.java:43-43: Implement a Smart decorator for... #505
Merge branch 'master' of https://github.com/jcabi/jcabi-github into 371
#564 - MkOrganizations.get() replace hard-coded created_at value with current time
#571 - Content.Smart#repo() method causes infinite recursion
Issue #371 Impl. Fix for hardcoded User instantiation
Merge pull request #526 from andrescandal/371

#526: pull request Issue #371 Implemented RtCollaborators methods and unit Tests.
#571 - Content.Smart#repo() method causes infinite recursion
#564 - MkOrganizations.get() replace hard-coded created_at value with current time (added missing unit test)