Allow null state object in response.

Also read contest level as array, rather than single string.
Merge pull request #66 from flibbertigibbet/feature/allow-null-state

Allow null state object in response.
Display error message to user if exception in querying
Merge pull request #67 from flibbertigibbet/feature/display-message-on-query-exception

Display error message to user if exception in querying