Return the empty string as appropriate for location.{search,hash}.
Improve error message for when web fonts fail to load.
Merge pull request #3083 from glennw/font-cache-error

Improve error message for when web fonts fail to load.
Merge pull request #3081 from Ms2ger/location-empty

Return the empty string as appropriate for location.{search,hash}; r=Manishearth