vpxpes_parser: Add start code emulation prevention support.

Remove bytes inserted to avoid start code emulation. Operates on:
- PES optional header
- BCMV header
- payloads.

Transforms the following byte sequences as noted (left converts to
right):
  0x00 0x00 0x03 0x01  =>  0x00 0x00 0x01
  0x00 0x00 0x03 0x03  =>  0x00 0x00 0x03

Change-Id: I09ae2d5bf03dfc1ade785ee89a773509eca8330c
3 files changed