Easier input on some more modern devices

[zenorogue]

I have implemented some features to make IVAN easier to play on some modern devices.

• Diagonal directions can now be entered by pressing Left/Right together with Shift/Ctrl. This control scheme is used in some other roguelikes as a way to make the game easier to play on laptop keyboards that do not have numpad.
• The 'keyboard layout' command is now a selectable list. It is possible to launch a command directly by choosing it from there.
• Implemented basic controller support. Movement (and other directional input) is done by pushing the joystick in the desired direction and pressing Ⓐ (this seems to be the standard roguelike controller support). Pressing Ⓨ in the main command interface yields the keyboard layout screen. In lists, D-pad sends arrow keys, Ⓐ selects, Ⓑ cancels, Ⓧ/Ⓨ work like page up/down. Also the game reacts to controller input in some other questions.