'location.origin' is undefined in some IE versions

[xsc]

In some IE versions, location.origin (or window.location.origin to fully specify it) is undefined [1], resulting in this piece of pushy's code to generate the pattern #"^.*$" - which always matches.

If you're okay with it I'd open a PR implementing the workaround described in [1].

[1] http://tosbourn.com/a-fix-for-window-location-origin-in-internet-explorer/