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)

Any reason these aren't simply declared inside the loop? (They are reinitialized at the start of every iteration anyhow)