Remove store reverse_proxy helper.

The Pyramid way is X-Vhm-Root.
Revert "Tweak the tag editor widget to to propagate click events"

This reverts commit a686e540ee3a012cc7dbec50ac5d3f07fc5f75cd.
Restore reload_templates setting
Rework thread collapsing and editing interaction

Thread collapse handling is moved to the thread directive. This
directive no longer creates new scope (since the tranclusion of the
recursion was making it hard to propagate events up the thread
scopes).

Now, which children are being edited is tracked by every ancestor
so that threads cannot be collapsed if editing is taking place
below.

Fix #555
Save edits uncollapsed
Don't propagate tag clicks
Cursor pointer on all threads
whitespace
Add a sleep in functional test for sauce
Fix virtual rooting of the api