The initialization of SynthUnit changed (a long time ago), but the Mac
app was never updated. Note, the Mac app probably still needs
hand-editing so it can find the ROM file, and maybe also the MIDI
device.
Changed toolchain to "clang", set "-Ofast" so that the code is
compiled with proper optimization, and fixed some code errors
uncovered by clang's more aggressive optimization.
This commit makes the project build on Android Studio. It also deletes
a whole lot of unused code. Further, in this patch, the NEON code is
not build, just C++.