Initial timecodes support in the main script, possibly broken
Add tests for timecodes support in demuxing
Simplify frame size calculation

Instead of calculating average of two frame sizes at specified point, we calculate only the requested frame. This is easier, safe enough and also fixes a bug with wrong result for v1 timecodes with override blocks
Everything throws a custom exception instead of exiting directly
Add some tests for the main script files validation

Won't work because you probably don't have the media files