gui: save/restore last folder outside repository. Closes #476

artiq/dashboard/explorer.py

@@ -298,3 +298,11 @@ class ExplorerDock(QtWidgets.QDockWidget):
 
     def update_cur_rev(self, cur_rev):
         self.revision.setText(cur_rev)
+
+    def save_state(self):
+        return {
+            "current_directory": self.current_directory
+        }
+
+    def restore_state(self, state):
+        self.current_directory = state["current_directory"]

artiq/frontend/artiq_dashboard.py

@@ -145,6 +145,7 @@ def main():
                                        sub_clients["explist_status"],
                                        rpc_clients["schedule"],
                                        rpc_clients["experiment_db"])
+    smgr.register(d_explorer)
 
     d_datasets = datasets.DatasetsDock(sub_clients["datasets"],
                                        rpc_clients["dataset_db"])