link all the PCL components with PCLPlugin to avoid the link error
PositionDragger::sigPositionDragged is emitted when the contained object is dragged
Specify minimum required PCL libraries to link with PCLPlugin
Disable the option to link with the static ODE library by defalt to avoid a trouble when the Gazebo's ODE is not used
allow the background executions of other python scripts when PythonConsole is waiting for input