ever implemented for OpenGL2 driver, lots of code debt, best to
instead just keep improving the overlay system instead which is
already available for most video drivers
* Add intrinsic NEON versions for float_to_s16/s16_to_float courtesy
of davidgfnet
* Define -DDONT_WANT_ARM_OPTIMIZATIONS for resampler sinc - this should
default to intrinsic versions
* Default to ARM NEON intrinsic codepath and make the ASM codepaths
optional by defining HAVE_ARM_NEON_ASM_OPTIMIZATIONS
* (Pkg/apple/Android) Take out ASM files being compiled in
