More work on the testing framework.
Messing with the names and declarations of a few enums and typedef structs.
Some bounds checking for MADSoundDriverIsAvalable:
we don't want an overflow when passed a really large value.
More KVO work.
Make isPlayingMusic available again in PPDriver.
More work on Pcmd handling on PPPatternObject.
Changing the signatures of a few PPDriver Swift extensions.
Minor changes to the MIDI plug.
Although the changed code doesn't seemed to be used anywhere…