[Suggestion] In EmulationStation be able to run specific emulators per game

Hey it would be cool if we could run specific emulators for a specific game that does not run in the default emulator playlist.
I’m going on holidays for about a week or so but when I get back I will probably implement this.

off note:
Also I got some code to be able to run advmame with different input button assignments, when I get back I’ll tidy it up a bit and there is a bit of code I want to modify which I will release.
It’s handy for games like Mortal Kombat and Street Fighters to work like there console versions on a PS3 controller.

Ok so Im back from holidays.

Emulator per game can already be set in ES so no changes needed there.

Advmame - Joystick Cfg changes are here, I will make a PR soon.

Here is the PR Change.