better debug, more consistent tick
performance tweaks
better sector algorithm, performance fixes
game mode for demo page
various fixes/enhancements

grenade blasts now have kill / maim / stun / distract radii. distract means
that nearby zombies will go check out the explosion before resuming the hunt
for braaaaaaains

a few bugfixes and performance tweaks... avoid sqrt whenever possible.
since we never need the true distance, the square is fine.

preparation for moar physics (e.g.
thrown grenades bouncing off zombies)
some grendade tweaks
perf tweaks
grenade sounds
minor refactor/cleanup
zomg coffeescript!
updated TODO/README
shadows, scorch marks and blood
fix some collision logic, start adding structures
fix stats
grenade physics, better collision logic

grenades (or rather, thrown items) can bounce off agents and structures
(stunning the former)

agents now do a better job of going around structures to reach their
target
first stab at motorhome, crosshair pointer

need to fix stacking issues, as well as rebound tangents and height

don't offset pointer above player, render it as a crosshair on the ground
when the player is tracking it

fix grenade crash
fix stacking issues for irregular structures
new structures, refactor

still need to fix stacking issues when multiple structures are in the same
x range
fix stacking, add scrolling
HUD tweaks, fix bullet render