Merge pull request #12 from jcabi/master

merge from master to my branch
Merge pull request #13 from jcabi/master

merge to my branch
Merge pull request #14 from jcabi/master

merge from master to my repo
Merge pull request #15 from jcabi/master

merge from master to my branch
Issue #117: Added RepoCommits
Label.Unmodified.compareTo() fixed
Unit test was added
Issue #170 Fixed bug where gists are looked up from the wrong URI.
Issue #24 Created PublicKey and PublicKeys interfaces.
Issue #24 Added RtPublicKey and RtPublicKeyTest.
Merge pull request #16 from jcabi/master

merge from master to my repo
Issue #24 Added RtPublicKeys, RtPublicKeysITCase, RtPublicKeysTest.
Issue #24 Added MkPublicKey, MkPublicKeys, MkPublicKeyTest,
MkPublicKeyTests classes. Added User.key() method.
Issue #18 - Gist.java:55-55: Gist comments was implemented
Issue #18 - fixed
Issue #117: Added tests and stubs
Issue #164: Added test for Issue.Smart.roLabels()
Issue #164: Implemented Issue.Smart.roLabels() and minor fixes
Issue #180: Added tests for RtReleases.get() and MkReleases.get()
Issue #180: RtReleases.get() and MkReleases.get() implementation was added