explicitly register the coffee extension per the CoffeeScript 1.7 updates
Merge branch 'coffeescript-1.7-fix' of https://github.com/DocuSignDev/grunt

* 'coffeescript-1.7-fix' of https://github.com/DocuSignDev/grunt:
  explicitly register the coffee extension per the CoffeeScript 1.7 updates
updated the version regex to actually check for 1.7.* and above
changed pkg.json to reflect proper coffee-script version to use