add connecting to custom port

[mhbahmani]

No description provided.

[mhbahmani]

Closes #29

[melbahja]

Can you use net.SplitHostPort ? and make the default port 22

[mhbahmani]

Now check it out please.

[SegFault42]

Possible to merge it please ?

[melbahja]

This will break v1, it's gonna be in v2

Alternately if you want to connect to a custom port u can do:

user := "user"
addr := "127.0.0.1"
port := 22
// auth := your auth 

callback, err := goph.DefaultKnownHosts()
if err != nil {
   // handle err
}

client, err := goph.NewConn(&goph.Config{
  User:     user,
  Addr:     addr,
  Port:     port,
  Auth:     auth,
  Timeout:  goph.DefaultTimeout,
  Callback: callback,
})