Move part of the input module to Cryville.Input.

Assets/Plugins/Cryville.Input.Unity.Android/NativeMethods.cs

@@ -0,0 +1,9 @@
+using System.Runtime.InteropServices;
+
+namespace Cryville.Input.Unity.Android {
+	internal delegate void AndroidInputProxy_Callback(int id, int action, long time, float x, float y, float z, float w);
+	internal static class NativeMethods {
+		[DllImport("AndroidInputProxy")]
+		public static extern void AndroidInputProxy_RegisterCallback(int hid, AndroidInputProxy_Callback cb);
+	}
+}