Multiple result sets

Added support for multiple result sets returned by the .query promise. Please note that this is a breaking change from v1.0.x.

For example it is now possible to execute multiple queries in one call:

let command = `
    select * from account;
    select * from address;
`;

db.query(command)
.then((results) => {
    console.log(results[0]);
    console.log(results[1]);
},
(err) => {
    console.log(err);
});

The result will be an array of results instead of one array being the first result set.

Note: Multiple queries are not supported if you are using Visual FoxPro OLE DB Provider.