Corrections in SQLCancel

This something that is better to do in next version series and not to change behavior in current versions.
Currently SQLCancel does not guarantee it cancels execution of exactly the requested statement. It's more like SQLCancelHandle on connection - it cancels currently executes sql statement.
Other changes - for ODBC2 it should only close cursor and nothing else. For ODBC3 - either reset "need data" state if statement is in that state, or kill the query at the server, if it's executing. But maybe it still have to cancel function execution, if SQL is not run at the server yet.