Patch for handling unknown data types in jdbc driver

Attached is a patch which deals with

select 'id' as xxx from table

The issue is:

When the driver gets a data type which does not map into the SQL.Types
it attempts to load the object into a java object. Eventually throwing
an exception indicating that the type "unknown" was not found.

Since the backend defaults "unknown" types to text it was suggested that
the jdbc driver do the same. 

This patch does just that.

I have tested it on the above select statement as well as a small
program that serializes, and deserializes a class

Dave