R1:4d5badeec071

Quicksand - provide some plumbing for fancier updates

Summary: Ref D12448. Ref T7573. This changes quicksand up a bit so rather than caching just rendered HTML we also cache the initial response from the server. We also fire off a quicksand-redraw event which will let things like the page objects for notifications update correctly while using Quicksand (see D12448).

Test Plan: loaded up /p/btrahan/ Clicked the UI elements to navigate to various profile views up to maniphest. clicked back until back at…