UTTypeCopyPreferredTagWithClass returns nil mimetype for css when there is no network
Merge fix for CB-6532 (This closes #55)
CB-6571 Fix getParentForLocalURL to work correctly with directories with trailing '/' (This closes #58)

Fixes 2 failing unit tests in mobile spec.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/cordova-plugin-file