Removed unnecessary imports, obsolete or duplicated "docstrings" and updated comments
Making the repr of Pattern objects be a precise reproduction of it.

Also, to make the repr of Pattern objects easily readable, the repr of Track objects is indented.
Added the textual trackname field to the TrackNameEvent
Reverted untested last minute change, sorry
Merge branch 'repr-fixes'
Merge branch 'misc-cleanup'