Move sort headers out of directory layout.

This allowed some simplification of the sort component lifecycle.
Also move progress bar.
Also, don't reset model when we get a loader-reset when last results
reported "loading". Fixes a bug where progress bar was being hidden too early.
Finally do a little pixel tweaking on sort headers and breadcrumb.

Change-Id: I49a2c70443edacfe911f692054e289bf1d5f6ecb