cremalab/holidays-game — pull request #31 by albatrocity (2014-12-11 20:25:25+00:00)
Title: callbacks for leaving/entering proximity of an obstruction. hooray

Adds ability to set a `proximity` attribute on obstructions.

```coffee
id: "table"
src: "images/table.png"
x: 260
y: 400
proximity:
radius: 100 # within 100 pixels of the hit area
onEnter: (item, options) ->
console.log "ENTERING RADIUS"
onLeave: ->
console.log "LEAVING RADIUS"
```