Add additional deep-type auto-conversions

[Oceanswave]

There are some additional auto-conversions to consider:

• [x] Add support for indexed properties
  • [x] Iterators/IEnumerable/IEnumerator
• [x] Compiler created iterators coming from functions using the yield statement
• [x] Unwrap nullable values
• [ ] When projecting nullables to types, check HasValue to determine if the property should be set.
  • [ ] Enum values should auto convert
  • [ ] Generics (Maybe just testing. Concrete classes should just convert)
• [ ] Arguments associated with an Event (BaristaTypeConversionStrategy.cs - invokeListener)
• [ ] Types encountered in method/constructor/property parameters
• [ ] DateTime <-> JsDate (when implemented)

[Oceanswave]

For enum values, see https://basarat.gitbooks.io/typescript/content/docs/enums.html#enums-are-open-ended