Basically now gravity makes you 'press down' onto horizontal surfaces so freedom['y-'] works as expected. If/when this switches to acceleration this will no longer be an issue because there will always be downward force.
Fixing super-jump when you hold down space. We shouldn't add velocity vectors as long as we have a velocity model. Only set them.
Merge pull request #5 from dariusk/master

Hack so you don't skate/hover imperceptibly above the ground every other frame