Notify user if pointing to incorrect FluidSynth architecture

[sukerokushin]

this is a bit of a PEBKAC but i spent actual days trying to figure out why fluidsynth wouldn't load for me until i pointed foo_midi to a 32-bit version on a whim (my jaw subsequently dropped to the floor after clicking help->about and seeing x86). i think it would greatly help everyone if there were some kind of robust, specific error or the like thrown to foobar's console if you load a mismatched dll instead of Literally Nothing