Add support for muxing to libwebm.

Squashed commit of the following:

9f73b86 Updated code to Google C++ style guide.
8580901 Added support for linux.
fd0b59c Fixed segment size issue.
d51d5ef Added more Track and Video options.
0fc73fd Fixed issue where cue point was being written out on wrong
        track.
fcfdd07 Updated sample_muxer to read in a webm and output a webm file.
        Added some options to sample_muxer. Fixed writing out unknown
        size.
285c558 Added support for muxer guideline "Audio that matches video key
        frame should be in the same cluster." Added support for
        block_number in cue points. Added support for setting max
        cluster size.
f956dec Add support for setting the max duration for all clusters.
92ca53e Add support for Cues element.
d6b4cba Added typedefs for unsigned long long, long long, and unsigned
        char. Reformated some code.
1b1f8b2 Added support for SeekHead element. Added WriteVoidElement
        function.
8faa187 Add support for CodecPrivate. Add support for updating
        SegmentInfo duration. Add support for updating Segment size.
        Added new sample that swicthes the tracks.
1dd3555 Refactored some code. Check to see if track is a video track if
        starting a new cluster on a key-frame.
1bc8374 Refacotrs code so Cluster is in charge of wirting out its own
        data.
836cd74 Added basic cluster and simple_block support for writing frames.
cc48cc2 Add simple support for Audio tracks.
4efd614 Added support for using the encoded ID value for the elements.
fb8b5a6 Initial commit of libwebm muxer.

Removed switch_sample project. Fixed initialization order warnings on
Linux. Reformatted code to follow Google C++ style guide. Fixed Makefile.
Removed tester.cpp.

Change-Id: I4857042f804edb834be52787a7d5ccdd578b7275
13 files changed