Opus release 1.2-beta

This release fixes a bug in surround encoding causing very bad quality
on signals beyond a certain amplitude. Also included are a few ARM Neon
optimizations and some low-bitrate quality tuning.
Fixes some fixed-point 16-bit int overflows

The code would have run fine on 32-bit archs, but would have overflowed
on a 16-bit arch
2 files changed