Fix back/forwards behaviour and titles.
Merge branch 'ui' of https://github.com/mozilla/dxr into ui
Don't update the history state after searching until a longer timout (2s) expires.
Work around Chome's broken load/onpopstate behaviour
Revert accidental change to the trilite pinning.
Update URL as you search. Close #232. Fix bug 843344 and 837299.