improve IRC messages

Correct irc_reset_color value.

Messages to IRC are restructured and show commit titles when only one
commit is pushed.

Compare the old
 [awbot] LIVE fsckd pushed 1 commit to refs/heads/master
 [awbot] fsckd pushed 5 commits to refs/heads/master
 [awbot] fsckd pushed a new branch
 [awbot] LIVE branch changed from refs/heads/master to refs/heads/nova
to the new,
 awbot|master LIVE fsckd pushed a commit: redo IRC messages
 awbot|master fsckd pushed 5 commits
 awbot|nova fsckd pushed a new branch
 awbot|master->nova LIVE branch checkout by fsckd