Add set_uid() to mkvmuxer::Track.
Add set_uid() to mkvmuxer::Track.

Allow users of libwebm's MKV muxer to control the Track UID. This,
for example, allows creation of tests that rely on checksum comparisons
to verify output from the library.

Change-Id: I8b052e6dd5af734d76122b2a1b6b16382ffba214

reimaginemedia/webm.libwebm,jdm/libwebm,Acidburn0zzz/webm.libwebm,felipebetancur/libwebm,kalli123/webm.libwebm,webmproject/libwebm,pcwalton/libwebm,abwiz0086/webm.libwebm,Maria1099/webm.libwebm,Suvarna1488/webm.libwebm,webmproject/libwebm,webmproject/libwebm,felipebetancur/libwebm,kim42083/webm.libwebm,ericmckean/webm.libwebm,iniwf/webm.libwebm,zofuthan/libwebm,zofuthan/libwebm,gshORTON/webm.libwebm,matanbs/webm.libwebm,kleopatra999/webm.libwebm