osx ssh config to talk to Fermilab

macOS has a bad habit of messing with your `ssh` configuration.  As of 8/23, this setup should allow you to ssh/scp 

edit `~/.ssh/config`  to contain:

```Host *.fnal.gov
GSSAPIAuthentication yes
GSSAPIDelegateCredentials yes
ServerAliveInterval 30
ServerAliveCountMax 5
TCPKeepAlive yes
ForwardX11Trusted yes
ForwardX11 yes```

likely we'll need to keep updating. 