IReadOnlyList and IReadOnlyDictionary support
Duplicated List/Dictionary tests for IReadOnly* versions

And this led to some fixes for missing serializing/deserializing
Fix for #71

Removed BindingFlags.DeclaredOnly to find fields/properties. I don't see
the need to make this an option, because if the fields exist in both the
json and the object then they will be deserilized; otherwise they won't.
DRY Deserializer TypeCaches
fix a verification bug in the DEBUG build around read-only lists
update .gitignore
2.1.1
DRY serializer TypeCaches as in #78
Merge latest master