SpaceButton:

Code for a Nanode based networked on/off status button.

To compile, you need the techinc-fork of the EtherCard library
which can be found at:

https://github.com/techinc/ethercard

(The fork adds a polling interface for DHCP and DNS.)

The status LED should be connected to LED_PIN such that
a LOW output state will make it light up.

The button should be connected such that it pulls down BUTTON_PIN.
The code assumes a circuit breaking button, change BUTTON_PRESS
to LOW for a circuit making button.