Cosmetic enhancements to Supervisor.cpp

[AZero13]

Those empty braces are ugly.

[KSSBrawl]

I've been mulling over this one, and while I agree the empty braces are ugly, it would probably be better to leave them. I'm guessing the reason the code looks like this in the first place is because ZUN originally had code in those blocks, and then realized he didn't need that code and commented it out, assuming the compiler would be smart enough to not generate terrible code (unfortunately, MSVC is not a smart compiler.)

Regarding the other changes, I am willing to merge those into the repo. It's a shame we don't have any versions of this code that were compiled with debug code gen to actually be able to tell for sure if those are of the form

else
{
    if (...
}

or of the form

else if (...