Update README.md
expose redirect url setter to OAuthActivity
cleanup
Merge pull request #27 from box/exposeredirecturl

Exposeredirecturl
Update HelloWorldApplication.java
force hide oauth view if user doesn't want to show redirect url
Merge pull request #28 from box/sample

force hide oauth view if user doesn't want to show redirect url
Adds group support.
Merge pull request #29 from box/BoxGroup

Adds group support.