libstagefright: Make fully clang compliant

Summary:
fix alias violation in MPEG4Extractor
fix c++ narrowing violations in MPEG4Extractor
include #include <utils/Macros.h> where needed for DISALLOW_EVIL_CONSTRUCTORS macro

Test Plan: confirm functionality, confirm c++ narrowing static_cast logic

Reviewers: synergy, randall.rushing

Reviewed By: randall.rushing

Differential Revision: http://review.codefirex.com/D313