Merge pull request #19 from jcabi/master

merge from master to my repo
Merge pull request #20 from jcabi/master

merge from master to my branch
issue #234 RtGistCommentITCase.java:38-40: Integration tests for RtGistComment was implemented
Removed puzzle for Issue #97
Merge branch 'master' into 97
Merge pull request #21 from jcabi/master

merge from master to my branch
Merge pull request #23 from lthuangiang/master

merge from master to my branch
issue #234 fixed
Issue #231: Added tests for RtDeployKeys.get(), RtDeployKeys.create(), MkDeployKeys.get(), and MkDeployKeys.create()
issue #248 - fixed
Issue #231: Implemented methods RtDeployKeys.get(), RtDeployKeys.create(), MkDeployKeys.get(), and MkDeployKey.create(); minor fixes
issue #250 - fixed
Merge pull request #252 from lthuangiang/250

issue #250 - change NotNull message
Merge pull request #242 from carlosmiranda/97

Removed puzzle for Issue #97
Merge pull request #249 from lthuangiang/248

issue #248 - fixed
Merge pull request #251 from asinyagin/issue231

#251: pull request Issue #231
Merge pull request #237 from lthuangiang/234

#237: pull request issue #234 RtGistCommentITCase.java:38-40: Integration tests for RtGistComment was implemented