Collapse export into existing method, resolve outstanding issues

Library/ContentProviders/MeshContentProvider.cs

@@ -69,6 +69,11 @@ namespace MatterHackers.MatterControl
 							{
 								// TODO: Wire up caching
 								loadedItem = Object3D.Load(contentStream.Stream, Path.GetExtension(streamInterface.FileName), CancellationToken.None, null /*itemCache*/, progressReporter);
+
+								if (item is FileSystemFileItem fileItem)
+								{
+									loadedItem.MeshPath = fileItem.Path;
+								}
 							}
 						}
 					}