Added short description of page contents to test docstring.

The tests for the view are, in effect, the specification for the page.
Adding a short description of the page contents provides the background
information for the tests in each of the test cases for the view.
Renamed the css class used to mark counts of a species to entry-count.

This matches the the underlying model object and makes it easier to
understand the design. It also leaves the name "species-count" open to
be used for marking the total number of species seen.
Added the app for showing rare of interesting observations.
Added the app for browsing information on the species seen.
Added the app to support an RSS feed of the latest news updates.
The cms home page now redirects to the news updates page.