Fix shape not closed after using Fill Tool (#510)

* Always set shape property 'closed' on fill

* Remove closed property on Shape

* Make color mandatory in Fill

* Fix intersection for filled but open shapes

* Code style tweak

* Add TODO note to rework ClosePath check

editor/src/document/document_message_handler.rs

@@ -151,7 +151,8 @@ impl DocumentMessageHandler {
 			};
 
 			let (path, closed) = match &layer.ok()?.data {
-				LayerDataType::Shape(shape) => Some((shape.path.clone(), shape.closed)),
+				// TODO: This ClosePath check does not handle all cases, fix this soon
+				LayerDataType::Shape(shape) => Some((shape.path.clone(), shape.path.elements().last() == Some(&kurbo::PathEl::ClosePath))),
 				LayerDataType::Text(text) => Some((text.to_bez_path_nonmut(), true)),
 				_ => None,
 			}?;