Add support for Android 2.3+

There have been plenty of ppl involved in creating this version.
I don't wanna mention names as I'm sure I'd forget someone so I
just tell where help has been done:
- The partial android versions done by various ppl
- Testing on different android devices
- reviewing code (especially the in core changes)
- testing controls
- reviewing texts

A big thank you to everyone helping this to be completed!

src/tile.h

@@ -131,6 +131,25 @@ public:
 
 IWritableTextureSource* createTextureSource(IrrlichtDevice *device);
 
+#ifdef __ANDROID__
+/**
+ * @param size get next npot2 value
+ * @return npot2 value
+ */
+inline unsigned int npot2(unsigned int size)
+{
+	if (size == 0) return 0;
+	unsigned int npot = 1;
+
+	while ((size >>= 1) > 0) {
+		npot <<= 1;
+	}
+	return npot;
+}
+
+video::IImage * Align2Npot2(video::IImage * image, video::IVideoDriver* driver);
+#endif
+
 enum MaterialType{
 	TILE_MATERIAL_BASIC,
 	TILE_MATERIAL_ALPHA,