Hotkeys for cheats

[meekee7]

Players should be to bind cheats to keys. This matches the hotkey feature in ATX.

An obvious question is how to deal with cheats that require additional parameters. Key options include:

• Do not expose them to binding
• Cache the cheat arguments after their last command line invocation and reuse the cached data, do not execute the cheat if no cache data is present

Related to #158 and #159.