Add message option for to cli.rb
Manage messageToSave option in publish command.
Update help.rb
Merge remote-tracking branch 'pimpin/add_message_to_publish' into publish-message
Publishing command now supports custom commit messages.

Fixed and polished @pimpin's work.
Updated TravisCI settings and Gemfile so builds on Rubinius don't fail.

Additional requirements in Gemfile not necessary any more.
Merge pull request #35 from honzajavorek/publish-message

Publishing command now supports custom commit messages