Spring cleaning

Hi guys,

I recently used this lovely generator to create [this little presentation](http://jraasch.github.io/notes-jsconfeu-2013/). While I was at it I made some improvements to the generator. Mainly what I did was

* Remove `jquery` and `handlebars` deps.
* Instead render placeholer `section` elements with `grunt.template`.
* Which then also means that `js/main.js` can go.
* Clean up/update `npm` dependencies.
* Some `grunt` plugins have new/better APIs, which makes the `Gruntfile` easier to read.
* Add *linting* tasks.
* I also took the freedom to add a `Gruntfile` to the generator itself for a more convenient workflow.

Hope you don't mind the Coffee-Script :).