Detect cloud content corruption and inform the delegate.

[ADDED]     A method of detecting cloud content corruption.
[ADDED]     When the cloud content is corrupted, all devices unload the cloud store and inform the delegate.
            The cloud store will no longer be available until the corruption is cleared.
            The documentation specifies approaches the application can take to clear the corruption (WIP).
Implement cloud content corruption recovery methods.

[ADDED]     A method for migrating the cloud store to the local store.
[ADDED]     A method for rebuilding cloud content from the cloud store.
Fixes to cloud corruption handling and implement in example.

[FIXED]     Build fixes for cloud corruption handling code.
[FIXED]     Only reload the store on lack of corruption when it's detected as a cloud KVS change to avoid infinite-reloading of a non-corrupt cloud store.
[ADDED]     Recommended application handling code to the example.