#20 Added remove() method to Gists

Added remove(String name) method to Gists to delete a gist by name, plus
unit and integration testing.
Merge pull request #12 from jcabi/master

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

merge to my branch
#20 fixed code style

fixed code style.
#20 fixes
Merge pull request #14 from jcabi/master

merge from master to my repo
from master
Issue #21: Gist forking
Merge remote-tracking branch 'upstream/master'
fixed merge conflicts
Merge pull request #15 from jcabi/master

merge from master to my branch
#20 fixes
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into 20
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' into 20
#20 Solved RtGistsITCase
Issue #117: Added RepoCommits
Merge remote-tracking branch 'upstream/master'
Label.Unmodified.compareTo() fixed