Provide mechanism to get record type

It would be convenient to have some method on a `RecordWrapper` that allows retrieving the record's type. For example, a `get_type()` record might return a string `ao`, to say that this record is an Analog Out type, or `bi` for Boolean In, etc.

This would allow users to query `RecordWrapper` instances dynamically to know what keyword arguments `set()` allows, for example.