Add static method support to core Variant types

* Properly exposed, including validated and variant call
* Bound static functions in String and Color
* Did not add support for scripting languages, will have to be added manually.

core/object/method_bind.h

@@ -42,6 +42,7 @@ enum MethodFlags {
 	METHOD_FLAG_VIRTUAL = 32,
 	METHOD_FLAG_FROM_SCRIPT = 64,
 	METHOD_FLAG_VARARG = 128,
+	METHOD_FLAG_STATIC = 256,
 	METHOD_FLAGS_DEFAULT = METHOD_FLAG_NORMAL,
 };