[Android] Finish documenting the native functions in NativeLibrary.java.

Source/Android/src/org/dolphinemu/dolphinemu/NativeLibrary.java

@@ -15,8 +15,31 @@ import android.view.Surface;
  */
 public final class NativeLibrary
 {
+	/**
+	 * Handles touch events.
+	 * 
+	 * @param Action Mask for the action being performed.
+	 * @param X      Location on the screen's X-axis that the touch event occurred.
+	 * @param Y      Location on the screen's Y-axis that the touch event occurred.
+	 */
 	public static native void onTouchEvent(int Action, float X, float Y);
+
+	/**
+	 * Handles button press events for a gamepad.
+	 * 
+	 * @param Device The input descriptor of the gamepad.
+	 * @param Button Key code identifying which button was pressed.
+	 * @param Action Mask identifying which action is happing (button pressed down, or button released).
+	 */
 	public static native void onGamePadEvent(String Device, int Button, int Action);
+
+	/**
+	 * Handles gamepad movement events.
+	 * 
+	 * @param Device The device ID of the gamepad.
+	 * @param Axis   The axis ID
+	 * @param Value  The value of the axis represented by the given ID.
+	 */
 	public static native void onGamePadMoveEvent(String Device, int Axis, float Value);
 
 	/**