JS fix for when there are no invalid pages and user clicks revalidate invalid. Also validate unknown pages.

UI updates, show error and warning totals, allow user to click these and showcase the errors/warnings in a colorbox.

Add some validator improvements. Add a json validation results handler. Add some js for validating links. Modify page logger to always show the validation status, if known. Add some simple CSS.

Add method for determing the base directory of a URI. Keep the base we started at for comparison to ensure sub-uris match the original base. Canonicalize /dir/../ in paths.

First validate the URI, if the location is a redirect, just redirect them. Notify the user if there's no trailing slash.