[fluid-dev] Adding 8bit support.

[Carlo Bramini]

Hello,

I was wondering what you think and if it could be accepted the support of 8bit 
audio out samples.

This implementation required me to:
- add an fluid_synth_write_u8() function into src\synth\fluid_synth.c after the 
existing fluid_synth_write_s16() and fluid_synth_write_float(). Actually, it is 
identical to 16bit function, except that the samples are calculated in the 
range [0..255].
- add "8bits" option to the "audio.sample-format" setting.

In adddition to that, I suppose that also the documentation will need to be 
updated, if the "audio.sample-format" setting will support it.

Sincerely.