Add lab sheets
Explosion image + plus non-omniscient enemies
Load explosion.png plus tweak enemy sight range
Merge https://github.com/KWhite10/Four-to-the-Fifth into kasey
Merge Kasey's explosion fixes + cleanup
Merge https://github.com/kevcoxe/Four-to-the-Fifth into kevin
Cleanup kevin's HUD commits.

I removed the old commented out gui code. We're using git so that we
don't have to keep large chunks of old code sitting around.
Add starter lab tmx
Lab updates, some tiles still buggy
Add some enemies to lab map (Read details)

So the first map is now something I whipped up using the lab tileset
that Chi found. I really like how it looks, but Quintus or Tiled
likes to make things difficult.

Tiles weren't showing up in the collision layer, so I made a
background-obj layer below it, and then the tiles rendered fine.
Basically, background-obj is a redundant copy of collision, and
hopefully someone can figure out why they weren't rendering with just
the collision layer.

Otherwise, I think we have a nice tileset to work off now. Make sure we
give credit to the tilesheet maker at some point; don't want to get
sued.
Darken about page theme, add more visible play game button.
Update readme links
Incorporate story from wiki onto about page.
Tweak rocket explosion, and add rocket sounds.
Remove useless collision check
Fix rocket ammo not updating in HUD
Add loading text.
Add MUSIC_ENABLED global
Move Title scene into ui.js
Add some base classes and base colors to UI