Adds functionality and bind for toggling the minimap in-game

[mike9k1]

This seems to be a common request: apparently a lot of folks have some strong hatred for the minimap (mostly unnecessary or clutters the UI, I guess?). This just adds a bind to toggle it easily in-game.

I had actually made these changes awhile back and been testing on it since, no major issues found or reported back to me (ShockedHearts being the only other one i'm aware of using this fork) -- decided to finally submit a pull request when I realized I had forgotten about it for nearly a month