Add JavaScript State Machine downloader.
user
```coffeescript
handle = require 'knit-common'

user = 'jakesgordon'
repo = 'javascript-state-machine'
filename = if knit.min then 'state-machine.min.js' else 'state-machine.js'
ref = knit.args.shift()


if not ref or knit.help or knit.h
  console.log "Knit resource file for downloading the JavaScript State Machine library."
  console.info "Usage:   knit state-machine REF [--min]"
  console.info "Example: knit state-machine 2.1.0"
  console.info "         knit state-machine master --min"
  console.info "Options: --min flag downloads the minified version"
else
  exports.routes = {}
  targetname = knit.output or knit.o or 'state-machine.js'
  exports.routes["/#{ targetname }"] = handle.github(user, repo, ref, filename)
```
assistant