Adds alt attributes to fallback img elements.
Losslessly compress PNG images.
cosmetics
Modernizr is licensed under MIT license
.gitignore: sort entries by name
Update jquery.filedrop to the latest git.
Update README.md.

* specify the code language used
* Github uses https
Update html5 boilerplate to the latest git.
Update package.json.

* add bugs property
* specify minimum node.js version
Update markdown-js to 0.5.0.