Fix "ghosting" problem with buttons

[Jigoku]

Some button combinations cancel out others. Instead of "returning true",

function paddy.isDown(key)
	-- Check for any buttons which are currently being pressed
	for _,widget in ipairs(paddy.widgets) do
		for _,button in ipairs(widget.buttons) do
			if button.isDown and button.name == key then return true end
		end
	end
end

Change this to change the button state, eg;

paddy.dpad.buttons = {
	{ name="up",   x=paddy.buttonw, y=0, pressed=true },
...