implement some stuff to make exaple SDL app run

NOTE: the main addition in this commit is WIP support for apps which
render on an EGL surface obtained using ANativeWindow_fromSurface

currently, this EGL surface is obtained by creating a 700x700 pixel
window with GLFW (the 700x700 size is hardcoded in several places)
and only Wayland is supported

ideally, we'd want to use a wayland subsurface to position the EGL
surface above the Surface widget it's associated with (and do
whatever for X11)

src/api-impl/android/view/InputDevice.java

@@ -0,0 +1,11 @@
+package android.view;
+
+public class InputDevice {
+	public static int[] getDeviceIds() {
+		return new int[]{0}; // might work?
+	}
+
+	public static InputDevice getDevice(int id) {
+		return null;
+	}
+}