Support for finding symbols

Sometimes I'm not sure if I have used the name of my symbol already. If I use accidentally the same name twice, bad things will happen. With this simple approach I can check if there's other symbols with same tag name.

It's basically a copy of your file, but I removed bunch of code and added a simple counter with an alert. It would probably be prettier if we'd combine the common code into a library file and import the library or something.