MPEG4Extractor+MPEG4Writer:Bframes+EditlistSupport

Enabled BFrames encoding in ACodec. Added edit list box support
for B frames recording use case in Mpeg4Writer. Added edit list
support in MPEG4Extractor for video tracks with B frames and postive
CTTS entries. Also, fixed issues in the existing edit list support
for audio tracks.

Bug: 113022200
Bug: 113114128

Test: Recorded video in crosshatch and that played in synch on
      VLC Player-Linux, QT Player-MAC and test device/crosshatch.
Test: run cts-dev --module CtsMediaTestCases --compatibility:module-arg
      CtsMediaTestCases:include-annotation:android.platform.test.annotations.RequiresDevice
      A few test cases in MediaRecorderTest is failing, but those are
      failing without any of the code changes in this change list.
      A few of the test cases in MediaMetadataRetrieverTest are failing.
      Those cases didn't account for edit list entry in video file and
      hence those cases have to be modified.
Test: Simulated frame drops while B Frames recording, by skipping a few frames
      while muxing a video file with Bframes using MediaMuxer and manually
      checked values in CTTS table and also the elst entry in edts box.
Test: Checked playback of files in bug 113114128.
Test: Recorded video on crosshatch. Checked playback on Nexus 4 and
      Nexus 6.

Change-Id: I0cf7b26c0d6180b6bb7ad9924505823a629e55a0