Massive rewrite to AnimationTree. Many APIs changed in order to:

-Reuse resources
-Expose properties in AnimationTree

scene/scene_string_names.h

@@ -203,6 +203,8 @@ public:
 
 	StringName output;
 
+	StringName parameters_base_path;
+
 	enum {
 		MAX_MATERIALS = 32
 	};