update documentation

now shows how to use the methods included
move module.exports to the top

it is easier to see and does not clutter the bottom of the file
update method names to more conventional ones
update createRowStream to use streams2 implementation
implement where query for object to rowStream

createRowStreamWhere(err, table, obj);

where obj is an object of key value pairs
specifying an equality:

var obj = { field : value };
// SELECT * FROM 'table' WHERE 'field' = value;
implement where query for object to rowStream

createRowStreamWhere(err, table, obj);

where obj is an object of key value pairs
specifying an equality:

var obj = { field : value };
// SELECT * FROM 'table' WHERE 'field' = value;