Remove OIS.

This is in preparation for migrating to SDL2 input.

Issue #196.
Remove unused includes.
Implement initial keyboard support for SDL2.

Issue #196.
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.
Disable console actions for now.

We'll be implementing a new text input system based on SDL2 input.
Use SDL2 keyboard input types.
Route SDL input events to the controller.
Handle keycodes which are actually scancodes.
Route SDL input events directly to controller.

Deferring the events was causing quite a bit of weird input lag.  This
makes much more sense.

Also fixed the key pressed/released events being reversed.
Documentation and fixes for scancode hashing.
Implement SDL2 mouse input.
Init the SDL2 joystick subsystem.