Beefing up the cookies disabled check so that it handles almost all cases without user interaction.

* Add a new view, cookies_disabled - this is displayed to browsers that do not allow access to localStorage when cookies are disabled (Firefox, Chrome, Fennec)
* Add localStorage check in include.js to check for browsers that do not allow write access to localStorage.
* Add a Javascript cookie check in network.js->cookiesEnabled using a test cookie with duration of 1 second so it is never sent to the server.
* Remove the old cookies_enabled check that was theorized to come from session_context - remove this from the XHR mock as well.

issue #835