Urlencode parameters to linkRoute, for a valid URL

Without urlencoding these parameters

    link_to_route('resources.edit', "Link text", 'some id with spaces')

will fail: the generated URL will have the scheme and host repeated since isValidUrl choked on the space character.

See https://github.com/laravel/laravel/issues/2490 and https://github.com/laravel/laravel/issues/2491