[New Mapper] MMC5Plus: Extended MMC5 Mapper w/Compatibility

Here is the Nintendulator Base code for the Mapper at the current state...

This is not made by me, but rather a user by the name of "keyboardspecialist" on github, so any thanks goes to that person!

BTW It's currently set up as "Mapper #221/$DD", as it's not used right now...

Have a good time with it!

FCEUX currently assigns 221 to UNLN625092. Better use a number from the 256-511 plane, as it's less crowded. Note that Nintendulator by default does not support mapper numbers above 255. My implementation of Mapper 515 takes care of that as well.

using #2221