DDD - Final update (for this year)

I've got a music friend who likes to post "this is my final remix.............................. as an n-year-old" every year right before his birthday and I want to steal that for software dev now.

• This one adds a lot of work on the Tiled map import button. It's not done yet but it should be complete enough to pass usable data to the game, and clears up a bunch of edge cases that just used to just go ¯_(ツ)_/¯ with sub-par results
• Other than that I fixed a bunch of bugs and filled in a bunch of things that I had yet to implement, or in some cases, had implemented in a less-than-satisfactory way
• Lastly there's some UI cleanup. A lot of the event editor UI hasn't changed since almost the beginning, before I'd really settled on how it should look. so I spaced things out more nicely and added alphabetize functionality to Middle Click
• Squashed some graphical bugs, particularly in the event editor
• My mouse is perpetually half-broken and sometimes thinks the middle button is one of the other buttons for no reason, so I added an option to substitute Control + Space for it

Going to kill a bunch of compatibility in 2020.1 so that I can get rid of some really old code. Not sure how many yet, but you've been warned all the same.