UV nodes refactored

- Set the default value for uv input as 0, 0 to avoid errors when using with shader modes PARTICLES, SKY and FOG
- FlipbookUV node is now only available in shader modes SPATIAL and CANVAS_ITEM

addons/ShaderLib/Input/NodeScaleWorld.gdshaderinc

@@ -2,10 +2,10 @@ vec3 node_scale_world(mat4 model_matrix){
 	vec3 _axis_x = model_matrix[0].xyz;
 	vec3 _axis_y = model_matrix[1].xyz;
 	vec3 _axis_z = model_matrix[2].xyz;
-	
+
 	float _scale_x = length(_axis_x);
 	float _scale_y = length(_axis_y);
 	float _scale_z = length(_axis_z);
-	
+
 	return vec3(_scale_x, _scale_y, _scale_z);
 }