The InstrumentSelector keeps a PluginPtr reference to all
instruments. By default Ardour does not destroy the editor
at exit, So 3 instances of Instrument Selector can remain
* TriggerClipPicker in the editor sidebar (owned by _editor)
* TriggerClipPicker on the TriggerPage (owned by trigger_page)
* SoundFileOmega (sfbrowser owned by Editor)
If a shared_ptr reference is retained, VST3 Module is not
unloaded at exit. This leads to issues with various plugins.
eg. Reason Rack does not terminate, Ardour hangs at exit.
Copyright-holder and year information is extracted from git log.
git history begins in 2005. So (C) from 1998..2005 is lost. Also some
(C) assignment of commits where the committer didn't use --author.
