Minor performance tweaks for love::Type

On my system these tweaks restore performance to "enum" levels

--HG--
branch : dynamiccore2

src/common/types.h

@@ -38,17 +38,30 @@ public:
 	Type(const char *name, Type *parent);
 	Type(const Type&) = delete;
 
-	void init();
-	uint32 getId();
-	bool isa(const uint32 &other);
-	bool isa(Type &other);
-	const char *getName() const;
-
 	static Type *byName(const char *name);
 
-private:
-	static uint32 nextId;
+	void init();
+	uint32 getId();
+	const char *getName() const;
 
+	bool isa(const uint32 &other)
+	{
+		if (!inited)
+			init();
+		return bits[other];
+	}
+
+	bool isa(Type &other)
+	{
+		if (!inited)
+			init();
+		// Note that if this type implements the other
+		// calling init above will also have inited
+		// the other.
+		return bits[other.id];
+	}
+
+private:
 	const char * const name;
 	Type * const parent;
 	uint32 id;