Bumping to icheck 1.0.2

Ahoy!  Big fan of the rails gem you made for this.  I noticed it was a tad out of date so I bumped it to 1.0.2, made the tests pass for rails 3 and 4, and added a handy rake task to import the css and image assets in the future.  Let me know what you think and I would be happy to change anything else you need.

Thanks,
Ben