Get all settings for a host

[kke]

It seems every value needs to be queried separately.

It would be great to have something like:

   host, _ := ssh_config.GetHost("foo")
   fmt.Println(host.IdentityFile)
   fmt.Println(host.StrictHostKeyChecking)
   host.Port = 45
   fmt.Println(host.SSHConfig())

[NitroCao]

I think it would be better for GetHost method to return a map map[string]string.