WASD keys do not work with Dvorak layout in Firefox

[link2xt]

Input should use event.code instead of deprecated event.keyCode to make it work with Dvorak, AZERTY and similar layouts:

underrun/source/game.js

Lines 146 to 162 in f933e29

	_document.onkeydown = function(ev){
	_temp = ev.keyCode;
	_temp = key_convert[_temp] || _temp;
	if (keys[_temp] !== udef) {
	keys[_temp] = 1;
	preventDefault(ev);
	}
	}
	_document.onkeyup = function(ev) {
	_temp = ev.keyCode;
	_temp = key_convert[_temp] || _temp;
	if (keys[_temp] !== udef) {
	keys[_temp] = 0;
	preventDefault(ev);
	}
	}