Close inspector on model select

Previously we were getting this by accident as dm.Surface.branchNodes
had no 'end' property for a collapsed selection, so you always got
a contextChange when you went from a non-collapsed to a collapsed
selection, even if you stayed in the same link.

Change-Id: I868e1be4dc46c091a246a723c492c77e4efd24c4
Fix shift-click select on links in Chrome

Chrome tries to collapse the selection when you shift-click on them
because it forgets they're contentEditable. Detect this and fix it.

Change-Id: Ic52af6d14413bffdddb895c82512f7eb56b87dd9
Merge "Fix shift-click select on links in Chrome"
Merge "Close inspector on model select"