#48 Function for obtaining additional column info

[Jonathan Monroe]

This patch adds a new function for retrieving
additional column info when passing a MDBColumn
structure as an opaque pointer.

This patch is intended to supplement patch 1394058
"Functions for passing MDB types as opaque pointers",
but does not require it.

The attached diff file is based on CVS source on
2005-12-30.

[Jonathan Monroe]

Diff file for adding column info access function to libmdb source files.