WL#469: Descriptors Support

Affects: Connector/ODBC-3.53   —   Status: Complete   —   Priority: Medium

Add the support of complete descriptors to MyODBC 3.51 by implementing the
following APIs:

- SQLSetDescField
- SQLGetDescField
- SQLSetDescRec
- SQLGetDescRec
- SQLCopyDesc

and few misc options from statement and/or resultset attributes.