3 notable patches from lincoln (a) non-layered track mode (NOTE: this is broken for...

3 notable patches from lincoln (a) non-layered track mode (NOTE: this is broken for loop recording right now) (b) trim region to previous/next region (c) region push/pull trimming. work on these 3 features should be assumed to be still slightly ongoing (eg. default bindings and more). great stuff

git-svn-id: svn://localhost/ardour2/branches/3.0@4994 d708f5d6-7413-0410-9779-e7cbd77b26cf