add copyright notice and comment on free_connection
add copyright notice and comment on free_connection

sergeken/sqlpp11,rbock/sqlpp11,sergeken/sqlpp11,rbock/sqlpp11,volka/sqlpp11,rbock/sqlpp11,sergeken/sqlpp11,volka/sqlpp11,volka/sqlpp11,rbock/sqlpp11,sergeken/sqlpp11,volka/sqlpp11