Facebook iOS SDK 3.16.1

Summary:
    see https://developers.facebook.com/ios/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/ios/upgrading/
Facebook iOS SDK 3.16.2

Summary:
    see https://developers.facebook.com/ios/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/ios/upgrading/
Facebook iOS SDK 3.17

Summary:
    see https://developers.facebook.com/ios/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/ios/upgrading/
Facebook iOS SDK 3.17.1

Summary:
    see https://developers.facebook.com/ios/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/ios/upgrading/
Facebook iOS SDK 3.18

Summary:
    see https://developers.facebook.com/ios/change-log-3.x/

Upgrading:
    https://developers.facebook.com/docs/ios/upgrading/
Fix some namespace pollution in the static library.

This fixes namespace pollution, to prevent linker issues with apps and other
libraries with global symbols named eg. "kSDK".
Prefix defaultResultsLimit and defaultRadius.
Always renew the access token as we can never know if we're old or not
Make this at least work sanely on iOS 7
Let's not do this. We renew anyway and that will, in general, fix the fact that there was no error but also no token.
A cancel can also happen if the URL is fbconnect://success and there is an error_code of 4201.
Retry if it failed, falling back to the FB app or Safari