Public issue https://github.com/mackron/miniaudio/issues/323

This can be used for echo as well as a simple delay.

This uses https://github.com/blastbay/verblib to achieve the effect.

  * Biquad
  * LPF
  * HPF
  * BPF
  * Notch
  * Peak
  * Low / High Shelf

This is in preparation for some work in the high level API.

Public issue https://github.com/mackron/miniaudio/issues/101

Public issue https://github.com/mackron/miniaudio/issues/320

Public issue https://github.com/mackron/miniaudio/issues/319

This was happening specifically when uninitializing a data buffer while
it's still loading asynchronously.