Add copyright and license notice.
Move HashToString to its own translation unit.

This function will get rather large with the keyboard strings, so it's
better to have it in a separate file.
Remove OIS DLL build step.
Add string names for keycodes.
Use translated string for "Disabled".
Expose input hashing functions.

This is so we can we can use them to set the defaults in Util::Config.
Add TODO.
Use SDL keycodes.
Remove OIS build project.