Working Teleport Fast Travel System

Today I got my teleport based fast travel system working!

The gist of it is that you open the teleport window by hitting "t", and it offers up a selection of teleport nodes that you have activated on the map. The cost to travel to each one is listed next to the name. Choose your destination from the drop down menu, and click teleport to be taken instantly to the teleport gate, provided you have the required teleport fee. You'll need to slay a few slimes to earn teleport fees.

Hitting "t" again or clicking on the cancel button will close the teleport window without teleporting the player. The game is paused while the teleport window is open, so enemies will not move or attack during this time.

As usual, adding a new feature created interesting new bugs, which have also been slain now.  Initially the player would attempt to walk all the way back to the spot from which they departed upon arriving at the teleport destination, so I had to set a flag after each teleport to inform the system that any navigation clicks need to be voided out after a teleport, and this fixed it.

The plan is to add some sort of sound and visual effect for teleports, but currently it happens silently and without any fanfare.