simplify code related to selecting tracks. Add a TrackViewList object rather than "abusing" TrackSelection in lots of places. git-svn-id: svn://localhost/ardour2/branches/3.0@6358 d708f5d6-7413-0410-9779-e7cbd77b26cf
simplify code related to selecting tracks. Add a TrackViewList object rather than "abusing" TrackSelection in lots of places. git-svn-id: svn://localhost/ardour2/branches/3.0@6358 d708f5d6-7413-0410-9779-e7cbd77b26cf