* Added missing function definition for Goal 'on'.
The 'on' function is necessary to connect callback functions to events from ROS action goal 'timeout', 'status', 'feedback', 'result'.
* Increased version number after minor extension
* Changed datatype of 'end' param in to 'number'.
The end time should be also transmitted as a number in seconds like time t.
* Increased version number after minor fix.
