Targets should act as an override for the GITLAB_CHANNEL, appending targets to GITLAB_CHANNEL seems odd.  Plus the default value of #gitlab mucks things up with HipChat.
Document behavior of targets query string parameter.
Add 'last' command for details of latest build for specified job.  Have 'describe' command use configured URL for subsequent call for details of latest build.  Add help for 'last' command and include others in help index.
Merge pull request #1316 from pmotyka/master

Targets query string parameter should act as an override for GITLAB_CHANNEL