API CHANGE: Remove ma_src.

Resampling is now done through the ma_resampler API.

Note that with this commit the old sinc resampler has been removed
because it never worked properly and is going to replaced with a better
solution in the future. If you were using ma_src_algorithm_sinc you
should consider using ma_src_algorithm_linear with the linear.lpfCount
config variable set to MA_MAX_RESAMPLER_LPF_FILTERS.