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 always generates sidx box for segments for now. Change-Id: I61f71ebd281195b737902b57557a345c8e0b0c66