Added task status display to story list view

In combination with the aggregate task statuses coming back from the API,
this change surfaces those in the story list view. It also cleans up the
UI a bit, displaying only title, #, and aggregate status. Expanding the
row provides more details about the story's current state, as well as
revealing the description.

Change-Id: I28c2475f3322aa97d285c38b9b45576ca7c11ccc
Merge "Added task status display to story list view"