Catch std::exceptions thrown during startup
Use non-deprecated wxIMPLEMENT_APP
Move global_scripts to options.h

Not the perfect place for it by any means, but that's where the rest of
the application-global stuff is these days and it removed the need for
automation stuff to include main.h (and thus all the wxApp garbage).
Fix the Select All button in the import styles dialog
Update ffmpeg, ffms2, libass