Added CommentAdded::comment event attribute
Expose exit code and stderr of ssh commands

Raise non-zero exit codes together with stderr output.
Previously failing commands were silently ignored.
Merge pull request #18 from gluck/master

Added CommentAdded::comment event attribute
Merge pull request #19 from chgeo/ssh_stderr

Expose exit code and stderr of ssh commands
Updated changelog
Checkstyle fix
[maven-release-plugin] prepare release gerrit-events-2.2.0
[maven-release-plugin] prepare for next development iteration