Handle exit event, by stopping devices and disconnecting connections
Merge pull request #23 from hybridgroup/exit-event

Handle exit event, by stopping devices and disconnecting connections
Added new LinuxIO DigitalPin library.
Adde pure GPIO example and updated digital pin lib
Fix bug in GPIO example.
Updated IO and digital pin to use events.
Removed self and changed example.
Change event triggers in callbacks to fat arrows to keep obj scope.
Added close for GPIO and updated negative ifs
Change events and update example in digital pin.
Remove logging and update example.
Fixed missing mode variable in digital pin.
Updated digital pin lib and example.
Added new example for raspi adaptor.
Added new DigitalPin to Cylon core to use in adaptors.
Added new DigitalPin to Cylon core to use in adaptors, for real.
Refactored DigitalRead and setup mode to only emit connection event on connect.
Added new Digital read example for raspi, updated digitalRead in lib.
Adding interval reads to digitalRead.
Updated DigitalPin and raspi_button example.