Status API part 1: Small refactor of review request status methods.
Review Request #8298 — Created July 19, 2016 and submitted
We had some old code in
reviewboard.webapi.encoder
to convert Review Request
status values (such as "P" or "S") into nice representations for the API.
Similar methods for things like issue status lived as static methods on the
model. This change does the same for review request, so that it's clear that
we're referring to the review request status field rather than the new Status
model.
Ran unit tests.