Move JSHint config to jshintrc files

Follows-up 3f1f88b725.

Also:
* Moved jquery.cookie.js to src/ directory to allow using a separate
  configuration for it (also complements /build, and other jQuery plugin
  repositories).
* Simplified Grunt configuration.
Merge pull request #313 from Krinkle/jshint

Move JSHint config to jshintrc files