Add Valve class, change Makefile and Servomatic.ino

Add Valve class, change Makefile and Servomatic.ino

The main function needs to have init() before the declaration of first
Valve, because the Valve constructor needs the arduino initialized. One
cannot declare Valve before calling init().
Due to this and me liking variable declaration at the start of a
function, I've written the actual contents of main to a new function.