* bonus: one unconditional global listener less
* bonus: in FF the saved window size is restored on detaching
* theoretically possible drawback: 100+ editor tabs on a slow computer may be slower than before
kinda fixes#155
as per spec the fragment portion is ignored in @-moz-document:
https://www.w3.org/TR/2012/WD-css3-conditional-20120911/#url-of-doc
but we still respect url("foo#hash") set in userstyles
because the spec is outdated and doesn't account for SPA sites
collateral damage: simplified URLS.supported()
