Changed import workflow

-Rearrange favorites in fs dock with drag and drop
-Removed import -> sub-scene, moved to scenetree contextual menu
-Removed import -> re-import , moved and integrated to FS dock
-Added ability in FS dock to re-import more than one resource
simultaneously
-Added ability to drag from native filesystem explorer to Godot, only
works on Windows though
-Removed scene reimport merge options, never worked well. Eventually
merging materials should be re-added
-Added ability to set custom root node type when importing scenes
-Re-Import is now automatic, can be configured back to manual in editor
settings
-Added resource previews in property list for many resource types

tools/editor/scene_tree_dock.cpp

@@ -542,6 +542,10 @@ void SceneTreeDock::_tool_selected(int p_tool, bool p_confirm_override) {
 			}
 
 		} break;
+		case TOOL_MERGE_FROM_SCENE: {
+
+			EditorNode::get_singleton()->merge_from_scene();
+		} break;
 		case TOOL_NEW_SCENE_FROM: {
 
 			Node *scene = editor_data->get_edited_scene_root();
@@ -1696,6 +1700,7 @@ void SceneTreeDock::_tree_rmb(const Vector2& p_menu_pos) {
 
 	if (selection.size()==1) {
 		menu->add_separator();
+		menu->add_item(TTR("Merge From Scene"),TOOL_MERGE_FROM_SCENE);
 		menu->add_item(TTR("Save Branch as Scene"),TOOL_NEW_SCENE_FROM);
 	}
 	menu->add_separator();