Touch should allow custom plugin UIs to work properly with automation as the
generic UI does. IIRC this was requested for mixbus, however, no current
plugin UI I am aware of implements it, so it is completely untested.
git-svn-id: svn://localhost/ardour2/branches/3.0@11888 d708f5d6-7413-0410-9779-e7cbd77b26cf