improved camera

[freeman-lab]

Currently we are "yoking" the "lookat" style camera to the player by hardcoding a fixed relationship between player position and camera target and position, and the particular scheme doesn't account for rotation. We should fix this by tweaking this chunk of view.move

var t = transform.translation
this.camera.target = [t[0], t[1] + 20, 1]
this.camera.position = [t[0], t[1] - 60, 30]

where transform is the player's transform. Probably we'll just want to grab the rotation as well as the translation and then do the right calculation. Might also be cool to add more intuitive parameters (as opposed to several constant offsets).

cc @sofroniewn