Added servoWrite to adaptor.
Fix typo in param name in adaptor.
Fixed function call undefined in servoWrite.
Updated servo support to allow correct angle values.
Fix incorrect param name.
Fixed variable undefined issue.
Fixes adaptor typo in servoWrite.
Updated servo angle values in pwmPin.
Updated servoWrite allowed values for angle sent to pi-blaster.
Updated digital read to execute button callback and digital write to not add multiple listeners.
Merge pull request #3 from hybridgroup/20-raspi-adaptor

Added support for servo in pwmPin class.