Fixed warnings in MSVC.

It complained about undefined return values or using uninitialized variables.

src/Blocks/BlockButton.h

@@ -73,8 +73,13 @@ public:
 				return 0x0;
 			}
 		}
+		#if !defined(__clang__)
+			ASSERT(!"Unknown BLOCK_FACE");
+			return 0;
+		#endif
 	}
 
+
 	inline static eBlockFace BlockMetaDataToBlockFace(NIBBLETYPE a_Meta)
 	{
 		switch (a_Meta & 0x7)
@@ -93,6 +98,7 @@ public:
 		}
 	}
 
+
 	virtual bool CanBeAt(cChunkInterface & a_ChunkInterface, int a_RelX, int a_RelY, int a_RelZ, const cChunk & a_Chunk) override
 	{
 		NIBBLETYPE Meta;