... This seems the more portabe way to do it across platforms. We are not
relying on a passed-in TrackPanel, for the sake of keeping TrackInfo
independent of TrackPanel. We just get the active window from the
application, which should exists in all contexts in which the Settings are
demanded, which are drawing functions.
... Because of different ordering of file-scope static initializations, visiting
TrackInfo.cpp before wxApp is initialized. (This didn't happen on Mac.)
This requires other changes to PrefsListener so that safe unbinding is
guaranteed by destructors, even if the PrefsListener is destroyed after the
global wxApp object.
... eliminating some duplication in tables for Wave and Note track controls,
and freeing PlayableTrackButtonHandles from the big s.c.c, though in a cycle
yet with PlayableTrackControls
... and updating of them is accomplished privately in implementation files,
reducing intrusions into TrackPanel and ProjectWindow
This removes #include-s from TrackInfo.cpp, leaving dependency cycles better
than previously
