rake task for loading new entries
catch exceptions if fetch fails
reworks navbar

based on the splendid example at
http://getbootstrap.com/examples/navbar-static-top/
restores current user to navbar
introduces guest users
rake task to clear out guest users
introduces UserEntryReadings
doesn't show already-read entries on reading page
seed guest user accounts with subscriptions

It's worth noting that the _Wired_ and _Los Angeles Times_ stories
are displaying with a lot of awkward whitespace at the bottom,
indicating that the method for rendering entry content needs
improvement.