Marshalling: Non-generic collections

[jasongin]

.NET generic collection interfaces like IList<T>, IDictionary<T>, IEnumerable<T> are already supported for marshalling to/from equivalent JS collections.

This issue is about adding support for non-generic collections IList, IDictionary, IEnumerable and possibly some others.

I don't think non-generic collections are used much anymore, but maybe we should consider supporting them for completeness.

See also #242 about generic collection classes. We should also consider non-generic collection classes as part of this issue.

[jasongin]

The challenge with non-generic collections is that the element type is not known (AKA object). So the marshaller needs to dynamically detect the type of each item and marshal it accordingly. So this is maybe related to #307.