Merge remote branch 'qatar/master'

* qatar/master:
  psymodel: extend API to include PE and bit allocation.
  avio: always compile dyn_buf functions
  Remove unnecessary parameter from ff_thread_init() and fix behavior
  Revert "aac_latm_dec: use aac context and aac m4ac"
  configure: tell user if libva is enabled like the rest of external libs.
  Add silence support for AV_SAMPLE_FMT_U8.
  avio: make URL_PROTOCOL_FLAG_NESTED_SCHEME internal
  avio: deprecate av_url_read_seek
  avio: deprecate av_url_read_pause
  ac3enc: NEON optimised extract_exponents

Conflicts:
	libavcodec/utils.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>