Update main.d

* Wait for all parallel jobs that depend on the database to complete - added from f86c4b9

src/main.d

@@ -1139,12 +1139,14 @@ extern(C) nothrow @nogc @system void exitHandler(int value) {
 	try {
 		assumeNoGC ( () {
 			log.log("Got termination signal, performing clean up");
-			// was itemDb initialised?
+			// Wait for all parallel jobs that depend on the database to complete
+			taskPool.finish(true);
+			// Was itemDb initialised?
 			if (itemDB.isDatabaseInitialised()) {
 				// Make sure the .wal file is incorporated into the main db before we exit
 				log.log("Shutting down DB connection and merging temporary data");
 				itemDB.performVacuum();
-				destroy(itemDB);
+				object.destroy(itemDB);
 			}
 		})();
 	} catch(Exception e) {}