... for functions in final classes.
override is like const -- it's not necessary, but it helps the compiler to
catch mistakes.
There may be some overriding functions not explicitly declared virtual and I did
not identify such cases, in which I might also add override.
... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
... the preference is independent of those in Interface and Recording
preferences, which affect meters, sound activated recordings, time track,
and Plot Spectrum
... Also removed one line from the track control drop-down, and changed
accelerators to more mnemonic choices.
Also the open page of View Settings... determines track view type after OK
