Update README.md
Stop running tests on iOS 6.0 since it is no longer supported by Travis CI

The SDK will still be built for iOS 6.0 in the short term.
Update the build script for Travis CI to not test iOS 6.0
Fix destination name in test script for iOS 7.1
Update redirect URI documentation in README

The API now requires that a redirect URI be provided. Old services will
continue to work as long as they aren't updated, but new services must
specify the special URI that the SDK uses.

Fixes #92.
Merge pull request #93 from gcurtis/update-readme

Update redirect URI documentation in README
Add BoxSearchRequestBuilder.h to BoxSDK.h so that devs don't need
to import it directly
Updated README to contain project status
Update the readme to clarify the OAuth2 login process
Close BoxAPIMultipartToJSONOperation when cancel uploading #76

Improve the handling of cancel for operations with streams
Merge commit '5b9af5cf7ad1a19eff911b2fee6ce16dfeaeab3b'