AddCmd with Name having spaces causes the command to not execute

using this example raises the error `Error: incorrect input, try 'help'`:

```go
shell.AddCmd(&ishell.Cmd{
Name: "test cmd example",
Help: "test cmd",
LongHelp: "Turn syslog OFF.",
Func: func(c *ishell.Context) {
c.Println("test")
},
})
```

tried like this:

```go
{
ishell_cmd := &ishell.Cmd{
Name: "test",
Help: "test func",
}
ishell_cmd.AddCmd(&ishell.Cmd{
Name: "cmd example",
Help: "cmd example help text",
LongHelp: "Turn syslog OFF.",
Func: func(c *ishell.Context) {
c.Println("test")
},
})
shell.AddCmd(ishell_cmd)
}
```

makes it print the help:

```
>>> test cmd example

test func

Commands:
cmd example cmd example help text
```