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.