New reworked AnimatedSprite!

-New SpriteFrames editor, with support for drag&drop, multiple animation
sets, animation speed and loop.
-New AnimatedSprite, with support for all the new features!
AnimatedSprite3D has not been updated yet.
-Added support for drag&drop to other editors, such as resourcepreload,
sample library,  etc.

core/object.cpp

@@ -463,6 +463,11 @@ void Object::get_property_list(List<PropertyInfo> *p_list,bool p_reversed) const
 	}
 
 }
+
+void Object::_validate_property(PropertyInfo& property) const {
+
+}
+
 void Object::get_method_list(List<MethodInfo> *p_list) const {
 
 	ObjectTypeDB::get_method_list(get_type_name(),p_list);