Improving Latex Export

I have a few suggestions:
1. We could use the tikz library `automata`, and then instead of `\draw`, we use `\node` and `\path`, which will yield much cleaner latex, and more importantly, more easily customisable.
2. I suggest we add an option to resize the nodes. I tried a few things on the exported latex but nothing worked. But it is much easier with the `automata` library.