This adds a new dependency with libfuildsynth. MIDI support
is built by default, but can be disabled if not desired.
All RTP songs should work well, but there are known problems
with other files (see README). Also, the pitch shift implementation
is somewhat poor and doesn't match RMXP (at least subjectively).
A soundfont is not included and must be provided by
the user themself.
This bug occured when starting playback of a stream, then immediately
stopping it, loading a different source, and starting playback again.
The real issue was that in stopStream(), the streaming thread had
not even queued anything yet, so it first decoded some data, then
started playing the source (which had already been stopped in the main
thread), and then finally saw the term request and stopped.
Instead stopping the source after the thread has definitely
terminated fixed the problem.
Very rarely rogue buffers would remain and play on loop on song
switch because we only ever cleared processed, not queued, buffers
from the source.
The correct way to completely clear a source's queue is to
simply attach a null buffer to it.
Previously, on creation, we would parse the entire map data,
translating it into and uploading vertices once, then rendering
the entire map on every draw (to keep the draw calls minimal).
This worked great for smaller and medium sized maps, but starting
with larger maps (200x200+) it doesn't scale as the GPUs vertex
processing/culling is overwhelmed by the amount of data each frame.
This rewrite instead changes the strategy to only processing and
uploading a small subregion of the map (the currently visible part)
and regenerating all buffers if this subregion changes. The amount
of data transferred is small enough that it can be done every frame
without causing lag.
The changes also have the convenient side effect that we no longer
require 32 bit indices in mkxp, easing the road to possible GLES2
support in the future.
