pull_dir pulls recursivly parent directories

pull_dir does not only pull child dirs of the remote dir but the whole ftp - site by walking throug with ../ 

as a workaround i added something like this:

```
 def pull_dir(localpath, remotepath, options = {}, &block)

# workaround
   if remotepath.include? '..'
     return
   end
```

   ....

this might depend on the ftp server and / or your client os
