Added Gruntfile for zip build process

I set up a basic grunt build process to create the downloaded zip for the gh-page.  Run 
```
npm install && grunt
``` 
to build the zip.  I will make the CSS to include in the zip. It would be nice to include the dependencies in a ```dependencies``` folder within the zip so users can get the versions of the dependencies that the library is tested with.

I also added a grunt task for jshint, which can be used to help maintain code style consistency. I spent a little time trying to set up continuous integration but I was having trouble with running qunit inside phantomjs, Ill try to get it working tomorrow.