Release v0.12.2

• Add a first draft of midi plugin
• A few gamepad improvements: fix X/Y position on Nintendo controllers, add LEFT/RIGHT_TRIGGER gamepad axis
• Now support parsing of bitmap fonts in XML format (original support still fully supported, both can be used seamlessly)
• Add clay_allow_default_{touches/mouse_wheel/context_menu} defines to make it easier to export a web app that don't block scroll when inside an iframe
• A few other minor fixes