parse, _typeCast should not be enumerable

[SystemParadox]

Result sets from node-mysql do not work with chai's assert.deepEqual function:

var assert = require('chai').assert;
db.query("SELECT 1", function (err, result, fields) {
    assert.deepEqual(result, [{ '1': 1 }]); // fails
    assert.deepEqual(result, [{ '1': 1, _typeCast: result[0]._typeCast, parse: result[0].parse }]); // works
});

The _typeCast and parse properties are enumerable, so chai uses them in the comparison. Please could these be changed to non-enumerable.

See also #349.

Thanks.

[dougwilson]

Since these are methods on prototype, using Object.define will not result in a performance penalty, so the request is reasonable. I set it for the next release.