Quicksand and Pholio - make mock edit work

Summary: Fixes T8036. In addition to making the mock edit work, this tightens quicksand code such that the correct page id is returned even if start() has not been called yet. It also tightens mock view where some functions should respect statics.enabled a bit more.

Test Plan:
clicked edit mock, mock crumb, edit mock, mock crum, edit mock, made edits and they worked! clicked edit mock, mock crumb, edit mock, mock crumb, edit mock, profile icon, hit browser back to edit mock, made edits and they worked!

also observed mock view page not occasionally wigging out from image_onload race not having statics.enabled respect during the above

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T8036

Differential Revision: https://secure.phabricator.com/D12739