Fix oauth client redirect_uri handling #211

- Make the redirect_uri comparison slightly loosing (case insensitive)
- For clients that have a redirect_uri without a http and domain, add the current
api domain.
- Update the migration script which creates our default client - always set
redirect uri to "/". The actual base url will get appended later. This
ensure the ushahidiui client can only ever be used to authorize the ui
not some other server.
Don't specify redirect_uri in oauth tests

This was failing because we didn't match the real deployment base url
and we're now testing for that correctly.
Comment on oauth client redirect processing on handling blank redirect_uri's
Merge branch 'master' into oauth-redirect-uri-fix
Merge pull request #219 from ushahidi/oauth-redirect-uri-fix

Fix oauth client redirect_uri handling #211