Rogue Runner v0.4 - Introducing Treasure Chests

The next addition to the game was treasure chests that can be opened and various items collected.
Initially, I just wanted to get the system in (and worry about the chest content down the line).

First, we added treasure chest placements to the room templates.
Then we trigger some UI that shows the contents of the opened chest.
At the moment, this is all placeholder. But I added a coins counter so that I could confirm something was being collected when the buttons were pressed.
I've also made things flash and bounce to give some visual feedback to draw the player's eye to what is happening.

At the moment, you can still move around when looking in a chest which causes issues. But I'll sort that when I get the proper turn-based system in place. ... Which is actually the next job.