--.FM2 is no longer a valid movie extension, so it is no longer counted as such in IsValidMovieExtension.
-Reused the code from PCE controller setting for NES.
-Seem to support 4 controllers for the NES now.
-General code cleanups.
TODO:
-Input from the 3rd and 4th controllers doesn't seem to be polled properly. Figure out what's wrong here.
-The copypasta from PCE to NES could probably be made into one function. The same could be said about many other portions of this code...DRY.
-Now that the mnemonics are fixed, I will have to write a proper converter for FM2.
--Once this is done, I will try the same for PCE, even if it can currently run natively.
---Once this is done, IsValidMovieExtension might as well be removed in favor of only accepting .TAS files and converting everything else.