made tanks and bullets smaller
added missing , and ;
added host to node server
commented out xhr polling
added remote bullets
changes players and obstacles arrays to private, created removePlayer function
spawn bullets at the end of the barrel
added bullet/tank collisions and player deaths
added enemy tank to solo (non node.js sockets mode)
added bullet sprites
added tank/tank and tank/map crashes
updated default map (4 squares)
dckuehn: Added tank sprite
Merge pull request #1 from dckuehn/master

dckuehn: Added tank sprite
updated tank sprite image paths
added url path for correcting sprite image paths
corrected sprite image paths
added basic object drawings in addition to sprites
adjusted tank size to match sprite size
added canvas save/restore around sprite drawings
added bootstrap, alerts, click to spawn, self destruct, and improved multiplayer functionality

-added bootstrap (and jQuery)
-improved multiplayer handling (separate player and tank objs)
-added alerts
-added click to spawn
-added self destruct
-added session id to interface
-renamed client side socket object
removed drawing tank collision box
added more kill messages