Merge pull request #62 from jcabi/master

merge to my repo
Merge pull request #63 from jcabi/master

merge to my repo
Merge pull request #64 from jcabi/master

merge to my repo
Merge pull request #65 from jcabi/master

merge to my repo
Merge pull request #66 from jcabi/master

merge to my repo
Issue #609 - MkRepoCommitsTest contains one-time variables
Issue #568 - Wrong URI of Public Keys API
puzzles fixed
Issue 619
Issue 619
Merge pull request #655 from lthuangiang/568

#655: pull request Issue #568 - Wrong URI of Public Keys API
Merge pull request #654 from lthuangiang/609

#654: pull request Issue #609 - MkRepoCommitsTest contains one-time variables
Merge pull request #659 from sanai56967/619

#659: pull request 619