Added skeleton code for retrieving subtitles
Work in progress
Using palette for subtitles
Switched to palette images
Moved util functions into separate file
Additional work done on subtitle code
Adjust API for subtitle
Added error handling for file header
Fixed subtitle bitmap copying
Fixed muxing during final second
Fixed ASS decoding/encoding
Added function for reading raw packets
Improve codec search function
More changes to packet functions
Revert "More changes to packet functions"

This reverts commit d1b4575b0f16e135c10833e870634aaee876330a.
Revert "Added function for reading raw packets"

This reverts commit 7ad27f6d789477b9492a5ae993bb396078395e72.
Updated stat function to yield more info
Allow changing of channels and channel layout
Added subtitles to sample video
Added test cases
Updated codec search routine