Improve OAuth configuration:

 - take client_id from ini file too
 - don't refer to localhost in redirect URI (helps w/ reverse proxy)
OAuth: parameterize the redirect host
Merge branch 'experimental_plus_plus' of github.com:bwallace/abstrackr-web into experimental_plus_plus
Add google account section to sample.ini
Merge pull request #86 from gertvv/experimental_plus_plus

Make Google OAuth configurable