Swimming, timers, and optimization

NEW THINGS

- completely revamped swimming mechanics

- a stopwatch tool, and the ability to create/set simple time trial routes

- major optimization and performance tweaks.

- lilypads, to make water more pleasant :)

NOTES

- with the performance tweaks, some pop-in when traveling between rooms should be expected. This is intentional; it is working as expected, and is the kind of issue that will be solved with tweaks to the level design, rather than code. During these transitions, slight dips in framerate are also expected. 

- certain carrier NPCs might fail to properly initialize when an object is placed on them. To fix this, simply remove the object, and place it again. If they are seen wandering around without any object attached to them; this is also a bug.

It's been a few weeks since I uploaded the first build of the dev sandbox, and I got a lot of great feedback. Luckily, one of the points brought up was something I had already been planning on addressing, which is that the swimming mechanics were pretty dreadful. Return is in a weird place because this was a project that I started very early on in my game dev career, and as such, a lot of the mechanics have needed massive overhauls to account for the fact that they were initially made when I just wasn't that good at coding. Swimming was one of the last remaining vestiges of that time, and it was way past due for an update.

Initially, swimming was meant to be the only significant change; as soon as I began working on it, however, I realized that a few other additions needed to happen. The other major feature included in this build is a timer system, that allows the player to create a route, and time how long it takes them to get from point A to point B. This is not only useful from a testing perspective, but it also serves as a precursor to the parkour time trials that I'll eventually be adding. 

In addition to the new features, this build also includes numerous changes to the game architecture which should greatly stabilize/enhance the fps.