SDK: Handle reachability issues

<a href="https://github.com/idokleinman"><img src="https://avatars.githubusercontent.com/u/6490062?v=3" align="left" width="96" height="96" hspace="10"></img></a> **Issue by [idokleinman](https://github.com/idokleinman)**
_Sunday Nov 16, 2014 at 21:42 GMT_
_Originally opened as https://github.com/spark/mobile-sdk-ios/issues/1_

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