Renames a field in the ResultSet.
Takes three parameters:
The first parameter is the name of the ResultSet whose field is being renamed.
The second parameter is the current name of the field.
The third parameter is the new name of the field.
Returns TRUE if the function is successful.
Returns FALSE if the function fails.
Renames the 'invoice' field to 'outlays' in the warehouse ResultSet.
<$exec rsRenameField("warehouse", "invoice", "outlays")$>