Fixed bug by which the plugin was not working with different child models of the iCub parent model
Update to new ControlMode2 and InteractionMode interface

ControlMode2 has been implemented
InteractionMode stores the new value and returns it back but does not
change behaviour of the robot
Fix memory leak introduced by https://github.com/robotology/gazebo-yarp-plugins/commit/e7509012a41899671475f55a05c3d367392ab036
Merge pull request #130 from robotology/fixMemoryLeak

Fix memory leak introduced by interaction mode support
Update controlMode logic to new standard
Add startup default value for interaction mode to STIFF
Merge branch 'master' into development