Work

Changes:
* added syntax aligned to pi_piper gem, more abstract
* add watch functionality to check for switch beeing presses (the functionality I need :-)
* try to added sunxi gpio PULL functionatliy to the c-library
/ http://www.cubieforums.com/index.php?topic=2881.15 / int sunxi_gpio_set_pull(unsigned int pin, unsigned int val) {
But addint to C-Library does not work - after buidling the Gem, it is not included.
* Moved Init functionality out of read function, as Init is only done once, and more then one pin may be defined (your comment)
* moved constants to separate file