Renamed course development grant page.
Added link to cluster.html
Refinements to cluster/course pages

- Updated cluster/course page ToC
- Updated stylesheet for left-hand ToC, image-resize, header font sizes
- Added cluster/course award images
- Linked CFP announcements on home page
Updated digital library slide.
added Symfony PHP application to handle email subscriber management

https://bugs.citd.tamu.edu/show_bug.cgi?id=* master