ui: Added custom trail dialog (issue #249)

* open custom trail dialg via button in top of trail controls
* search from symbol to symbol or all referenced/referencing of symbol
* define search depth with slider
* define horizontal/vertical layout
* define node and edge types
* renamed depth graph to trail in graph ui
* added custom trail UI tests

fortune cookie message = A happy surprise is waiting for you.

src/lib/component/controller/UndoRedoController.cpp

@@ -132,7 +132,10 @@ void UndoRedoController::handleMessage(MessageActivateTrail* message)
 		return;
 	}
 
-	Command command(std::make_shared<MessageActivateTrail>(*message), Command::ORDER_ADAPT, true);
+	Command command(
+		std::make_shared<MessageActivateTrail>(*message),
+		message->custom ? Command::ORDER_ACTIVATE : Command::ORDER_ADAPT
+	);
 	processCommand(command);
 }