Implement Run Helpers other than runAsync, like the ones provided by the RethinkDB C# Driver, as well as run*Async variances of them.

Suggested Run Helpers:

• runAtom<T>: Returns the atom value, possibly converted, or throws if not an atom
• runGrouping<K, V>: Same as runAtom but the result of the grouping operation is converted to Map<K, List<V>>
• runUnwrapping: Forces unwrapLists behaviour.