Add partitioning

Also add sd mounting/unmounting
Also add vol+/- controls for sideways menus

source/storage/mountmanager.h

@@ -13,4 +13,5 @@ int connectMMC(u8 mmcType);
 ErrCode_t mountMMCPart(const char *partition);
 void SetKeySlots();
 void unmountMMCPart();
-link_t *GetCurGPT();
+link_t *GetCurGPT();
+void disconnectMMC();