WME Subtitles

I've ported Mnemonic's subtitle code from WME1 and tweaked it to go with our style and conventions.

This seems to work well enough with both autodetected and 'regular' subtitle files from my demo game (mov_test from my repo wme_testsuite)

BTW - I tried to do some refactoring and prettifying on that function  because it doesn't look terribly pretty to me, but everytime I keep ending up with something that's different but no less ugly.