libstagefright: Extended media support via FFMPEG

 * Original work by Michael Chen - https://github.com/omxcodec
 * Original Kitkat port by Chih-Wei Huang / Android X86 project
 * Additional work up to Nougat by:
   - Steve Kondik
   - Ricardo Cerqueira
   - Keith Mok
   - Scott Mertz
   - Ethan Chen
   - Diogo Ferreira

Change-Id: Ie871b56f6f6d895a87de8c8920e9e8692382b420