Draft: Resolve "Enhance mupen64plus settings"
Compare with
https://github.com/RetroPie/RetroPie-Setup/blob/master/scriptmodules/emulators/mupen64plus.sh
and
https://github.com/RetroPie/RetroPie-Setup/blob/master/scriptmodules/emulators/mupen64plus/mupen64plus.sh
See options here: https://github.com/gonetz/GLideN64/blob/master/src/mupenplus/Config_mupenplus.cpp#L35
Closes #308