Added switch for fetching the full message in the iOS example app.
* Added per discussion in #93.
* Fetching the full message is disabled by default.
Added switch to settings view controller.
* Removed setting of user default in app delegate.
Fixed indentation.
* Consistently using spaces instead of tabs.
* Tab width is set to 4 spaces.
Merge pull request #131 from paulyoung/fetch-full-message

Added switch for fetching the full message in the iOS example app.