[138] Swallet

These past two weeks have been for the most part, pretty busy, stressful, and frustrating.

However, I did get some stuff done with the platformer, as well as a side thing.

I didn't realize how involved refactoring player movement to be more responsive until I actually started working on it, but I did eventually arrive at a solution I'm fairly happy with.

Basically, the movement now uses an easing function made from a cubic bezier curve.

Here's the code related to the platformer stuff:

I also did other stuff as a way to not get burned out from working on that single annoying problem for 2 weeks. Here's the code for a new SDL2-based library thing (currently a WIP):