Adding Demo apps for iOS SDK.

- These are the same apps that were in:
  https://github.com/attdevsupport/ATT_APIPlatform_DemoApps/tree/master/IOS
- They have been removed from the repo: `attdevsupport/ATT_APIPlatform_DemoApps`
Merge pull request #1 from pgpbpadilla/develop

Adding Demo apps for iOS SDK.