On logout, Post to account's logout location on server, so the session
cookie is expired.
Tests for logout, with the one new test still failing.

My attempt to get an additional respondsWith to catch the
accountModel.logout() method's POST to the logout address isn't yet
working.  Checking in for the evening.
Whoops - include the supplemental server.respondsWith().
Whoops instead - I had already included the second respondWith, in the
beforeEach section.
Missing response headers and this.server.respond(); in "should POST to the account's logout URL" test
Removed TODO as it's TODONE
Merge pull request #11 from SpiderOak/cookie-sanitization

Cookie sanitization