Add images to user and projects

Allow users to upload a photo of themselves and a project photo.
This commit includes: configure carrierwave, fog and aws, add
image columns to user and project tables, add image upload field to the user
and project forms, display image thumbnails in index pages, and display
 larger images on show pages. Rationalize some of the related CSS.
I'd think there'd just be validation so you could see the form if you weren't signed in? From what I can tell it seems like you could see the entire form, fill it out and then get to the bottom and realize you're not signed in ?