Update Grunt to v4.0
Update vendor files
Fix .travis.yml / Ignore temporary directory
Remove grunt.util.async / Fix the path to CoffeeScript compiler

* grunt.util.async is deprecated.
* See http://coffeescript.org/#changelog for details about CoffeeScript
1.7.0.
Fix coding styles according to JSHint

trailing whitespaces, unused variable declarations, and missing
semicolons
Add license statement for falafel

falafel is licensed under the MIT license
Merge pull request #379 from shinnn/master

Update dependencies and devDependencies (Close #376)