[libmix parser] Multi-thread parsing implementation.

BZ: 183804

1. Refactor h.264 parser to resolve logical and data structure dependency for multithreading
   and to improve PnP.
2. Two multithread parsing schemes were implemented: bundle input and sequential input.
   Default to bundle scheme.

Change-Id: I851419e079c9e0dd461337fd2be6627c88e0a294
Signed-off-by: Yuanjun Huang <yuanjun.huang@intel.com>
19 files changed