Removes the Java ButtonManager for one in the C++ source so the OSD class can call in to it each frame for drawing the buttons. Copy our assets to the dolphin-emu directory for now. Remove NativeRenderer, ButtonManager, and Button Java classes since they aren't used anymore. Buttons A, B, and Start all work and are drawn on screen now. Button input on Android is still a bit hacky, needs a proper controller interface still. Android specific button drawing code is still hanging out in SWRenderer.cpp