text.Shaper is not thread safe, which caused crash when adding
multiple VSTI plugins to a DAW project. This change fixes that
crash. Further refactorings need to consider where that text.Shaper
should actually reside.
The RPC and sync library mechanisms were removed for now; they never really worked and contained several obvious bugs. Need to consider if syncs are useful at all during the compose time, or just used during intro.