For mp4 outputs, a metadata box with version information is added to
moov box.
For mpd outputs, a text comment with version information is added in
the beginning of mpd file.
Issue #60
Change-Id: I783ba370781c0a8f77c910ff1172bad2e7edff75
Also update the code to generate CompressorName in VideoSampleEntry
for both AVC1 and various VP codecs.
Change-Id: I2355f8008a72806e852aa1ec6c80e9141b97d963