Add modal dialog for viewing photos.

Needs styling work.  In particular, there are z-index issues causing the modal
to appear under the grayed out background, and the close button does not align
on the popup.
Add endpoint for map feature photo rotation.
Add JS code for rotating images.
Style lightbox for photo carousel
Rework JS and CSS to work with Bootstrap 3
Merge pull request #1407 from maurizi/rotate-images-endpoint

UI for rotating images