Updated digital pin and added pwm raspi example.
Fixes err param not being passed.
Update digital pin close callback param.
Merge pull request #43 from hybridgroup/20-raspi-adaptor

Example for PWM support for the cylon-raspi.
Update to 0.6.1
Add more supported devices to README
Added servo example for Raspi.
Debugging digitalPin read.
DigitalRead buffer data converted to string now.
Update digital read to parseInt buffer response.
Updated servo examples to use a limit range of motion instead of full 180.
Merge pull request #44 from hybridgroup/20-raspi-adaptor

Added servo example for Raspi.
Crazyflies
Merge branch 'master' into literate

* master:
  Crazyflies
  Updated servo examples to use a limit range of motion instead of full 180.
  Update digital read to parseInt buffer response.
  DigitalRead buffer data converted to string now.
  Debugging digitalPin read.
  Added servo example for Raspi.
  Add more supported devices to README
  Update to 0.6.1
  Update digital pin close callback param.
  Fixes err param not being passed.
  Updated digital pin and added pwm raspi example.

Conflicts:
	examples/servo.coffee