Add IMeshBuffer::getType

Allows to find out which class a meshbuffer has.
I used the same kind of style as ISceneNode::getType. So using four CC codes and virtual functions (instead of type variable).

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6330 dfc29bdd-3216-0410-991c-e03cc46cb475

include/SSharedMeshBuffer.h

@@ -226,6 +226,12 @@ namespace scene
 		/** This shouldn't be used for anything outside the VideoDriver. */
 		virtual u32 getChangedID_Index() const IRR_OVERRIDE {return ChangedID_Index;}
 
+		//! Returns type of the class implementing the IMeshBuffer
+		virtual EMESH_BUFFER_TYPE getType() const  IRR_OVERRIDE
+		{
+			return EMBT_SHARED;
+		}
+
 		//! Material of this meshBuffer
 		video::SMaterial Material;