Expressions "1.2.3.4/" are not valid

> var test = new netmask.Netmask("1.1.1.2/"); // <= NO ERROR
> { bitmask: 32,
... maskLong: 4294967295,
... netLong: 16843010,
... size: 1,
... base: '1.1.1.2',
... mask: '255.255.255.255',
... hostmask: '0.0.0.0',
... first: '1.1.1.2',
... last: '1.1.1.2',
... broadcast: undefined }