Removed unused directives
Added arrayBuffer -> base64 function
Style cleanup for photo directive
Added image caching for better performance

Decided to stick with the _w vs _t image sets (they are bigger than we
need but look much better). Because of the large image size, using
indexeddb was much more practical than the original localStorage image
cache I first wrote.  Indexeddb has auto-notification if it gets too
close to IE’s limit for storage.  Still need to do some testing but
this should be a pretty good solution for preventing the constant
re-downloads.  It would be nice if SP would just send better headers…