Fixed a minor item physics bug that caused items to believe they
were on the ground for one frame after being thrown.

Nerfed the throwing speed to account for the increase in distance
caused by getting rid of the one frame of higher-than-normal
speed reduction (since being on the ground makes items slow down
faster)
Fixing a typo in some comments
Cleaning up image.js to be less ugly/better
Fixing image.js some more.