Fix a trailing comma.
Bootstrapped base template using Bootstrap 3.1.1 and JQuery 2.1.1

Closes #10.
Home page template based on Bootstrap Carousel and Jumbotron.
Add a Django template block in the base template to allow other templates to include additional CSS code.
Add a Django template block in the base template to allow other
templates to include additional JavaScript code.
Use holder.js to render image placeholders.

http://imsky.github.io/holder/
Simple navbar with login + signup buttons.

Closes #17.