Finally implements detune (using an approximation, but better than
nothing). Also minor improvements to note generation, including scaling
output level more accurately, and getting rid of dynamic allocations of
note objects.
We were only using a very few STL functions (min, max, and iostream for
debug logging). This patch gets rid of those dependencies (implementing
the needed functions in synth.h), and turns on the "all" ABI target, so
that it works with all native architectures supported by the NDK.
Raph Levien