Changed interface to NewHostname not to return error

This is more succinct for most uses.

commands.go

@@ -66,11 +66,9 @@ func Add(c *cli.Context) {
 	}
 
 	hostsfile := MaybeLoadHostFile(c)
-	hostname, err := NewHostname(c.Args()[0], c.Args()[1], true)
-	if err != nil {
-		MaybeError(c, fmt.Sprintf("%s is not a valid ip address", c.Args()[1]))
-	}
+	hostname := NewHostname(c.Args()[0], c.Args()[1], true)
 
+	var err error
 	if !hostsfile.Contains(hostname) {
 		err = hostsfile.Add(hostname)
 	}

hostfile.go

@@ -116,10 +116,8 @@ func ParseLine(line string) []*Hostname {
 
 	if LooksLikeIpv4(ip) || LooksLikeIpv6(ip) {
 		for _, v := range domains {
-			hostname, err := NewHostname(v, ip, enabled)
-			if err == nil {
-				hostnames = append(hostnames, hostname)
-			}
+			hostname := NewHostname(v, ip, enabled)
+			hostnames = append(hostnames, hostname)
 		}
 	}
 

hostname.go

@@ -28,11 +28,9 @@ type Hostname struct {
 	Ipv6    bool
 }
 
-func NewHostname(domain, ip string, enabled bool) (hostname *Hostname, err error) {
+func NewHostname(domain, ip string, enabled bool) (hostname *Hostname) {
 	IP := net.ParseIP(ip)
-	if IP != nil {
-		hostname = &Hostname{domain, IP, enabled, LooksLikeIpv6(ip)}
-	}
+	hostname = &Hostname{domain, IP, enabled, LooksLikeIpv6(ip)}
 	return
 }