its 16 channel wavetable/PCM chip, with (optional) stereo support.
Its also has envelope, this feature has similar as AY PSG's one but its shape is also stored at RAM, and each nibble in envelope data is for each output: so i decided to added some feature for more stereo-ish envelope.
Split: Envelope shape will be splitted to Left and Right half for each output.
HInv, Vinv: Envelope shape will be Horizontally/Vertically mirrored the left one.
Max sample length is sample bank size of Seta 2 arcade hardware (currently not emulated yet, nor it doesn't support on VGM).
Chip id is temporary, it can be changed with to suggestions.
this commit mostly rewrites the sample system.
as of now samples can be ADPCM, 8-bit, BRR or 16-bit
or something...
consider this VERY EXPERIMENTAL.
if you find any issues REPORT THEM immediately.
it's nearly 4am...
