Infinity playlab

- New Infinity skin for play lab
- Move some things into skin from blocks (I will still need to move some more, like the classes of projectiles)
- Changes tiles.js to constants.js since that's how it's being used.
- Get rid of SpriteFlags/Mask. Instead have each sprite store how many frames of each type of animation it has. Right now the infinity sprites only have idles (which is treat as normal). They will later also have turns.
- We want to animate our idle frames at a specific frame rate, regardless of the tickCount frequency. We accomplish this by looking at how much time has passed since the start instead of at how many tick counts happened.