This function will drop a txtSQL $table from a $db. If no database is specified, then txtSQL will delete the table from the selected database
Important- To achieve the same results as this function before txtSQL 2.2.2 RC2, use the execute() function
Note- If $tablename does not already exists, txtSQL will issue an error
Note- If no $db is specified and no database is already selected, txtSQL will issue an error
