All routes can now optionally be queried.

The raw query string will be passed as last argument.
Query string now parsed if Backbone.qs defined
Removed fragment stripper. Changes to query params will trigger route change.
Fragment now includes query string and hash for pushState.

Hash is only included when wantsHashChange.
Added query string parsing support for pushState with hashChange

Also includes rename of Backbone.qs to
Backbone.History.parseQueryString.
Search params.
Add Router#execute hook.
Merge pull request #2890 from braddunbar/search-params

Search params