fix($location): correctly rewrite html5 url to hashbang url

In situations where path() matched basepath and we needed to
convert from html5 url to hashbang url, the $location service
considered the url to be already rewritten, which resulted in
an error.
chore(Gruntfile): run webserver on 0.0.0.0

... so that we can access it from local VMs.

The security risk of doing this is very low since only the current
working directory is being made accessible to everyone. There is also
an option to run a local firewall, which is a better way to secure the
developer's machine anyway.