Merge branch 't/bitstream_improvements'

Merge branch 't/bitstream_improvements'

Cooking since 2014-04-22.

* t/bitstream_improvements:
  bitstream: Improve documentation.
  wma: Store ASF header info in afhi->techinfo.
  bitstream: Replace check for impossible condition by assertion.
  bitstream: Remove pointless variable "code_prefix2".
  bitstream: Micro-optimization.
  bitstream: Kill pointless variable "symbol".
  bitstream: Trivial coding style fixes.
  bitstream: Trivial spelling fix auxillary -> auxiliary.