Dirthead Demo Update!

I've uploaded a patch for the demo! Taking in feedback, I've adjusted a couple of little things -- mostly bug fixes, but I did implement an option to toggle how you control Dirthead's singing.

You can press a single button repeatedly to sing -- as originally uploaded -- or hold the button to continuously sing until the button is released. You can activate this toggle by selecting "Hold Button to Sing?" in the options menu.