Build out thumbnails for posts

[abeyang]

Sub-task of #14.

• Height of each image is 330px.
• Need to add post title and author name as well (make them bottom-aligned)

[abeyang]

HTML file: site/templates/default.php
LESS file: assets/bootstrap/less/a2f.bootstrap.less (this is used for all pages)

[abeyang]

Jordan, let me know if you're stuck with this -- this shouldn't take you too long.

If it's questions about LESS, just ask away here. Don't worry too much about the image fitting perfectly.. the more important thing is the layout, which shouldn't be too hard.