Support to specify geom column and select list with OGR, ODBC

[szekerest@…]

It would be greatly usable to support for specifying the geometry column
when using OGR ODBC driver.
The current implementation retrieves the geometry_columns table from the
database in order to determine the geometry column of the table which
causes an extra round trip to the server. For a suitable solution the
geometry column name could be specified in the connection string as the
table name.

It would be also helpful to establish the ability to specify the list of
the columns to select, what could restrict the amount of the data as the
user's will.