Add support for System.Collections in JsonConverter.ConvertToJson

[sshankar-rks]

Supported collection types are Hashtable, SortedList, ArrayList, Stack, Queue. BitArray is not supported. Don't think it will receive much usage.

Why:
I use this library for logging data structures in VBA. It's very easy to dump nested tree/list/dictionary structures using ConvertToJson rather than writing code to iterate over each collection. Since System.Collection collections are often used in VBA, I thought this was a good idea.

How:
Use existing JSON serialization code as much as possible: Map Hashtable and SortedList to Dictionary
Map ArrayList, Stack and Queue to Array.

Some bugs in .Net/COM/VBA had to be hacked around. See comment on Stack and Queue types in JsonConverter.bas

Deserialization: JSON doesn't support any of these types, so no code to change there.

[sshankar-rks]

Forgot to mention: Tests were also updated.

[Nick-vanGemeren]

Those aren't bugs, they're features :{ See Stack Overflow

I suggest applying a more general solution:

    Dim json_VarType As Integer:     json_VarType = VBA.VarType(JsonValue)
    Dim json_TypeName As String:     json_TypeName = VBA.TypeName(JsonValue)
...
    If json_VarType = vbString Then         ' (separate conditions for faster test)
        If json_TypeName <> "String" Then
            ' See https://stackoverflow.com/questions/55659056/why-is-vbas-vartype-function-saying-this-com-object-is-a-string-object-is-ins
            json_VarType = vbObject
        End If
    End If