[idl-generator] Add event handler support
Merge pull request #14 from deqing/event-handler

[idl-generator] Add event handler support
[idl-generator] Add test case for event handler

1. Add demoevent handler
2. Add reference of base to impl class to broadcast event
Merge pull request #15 from deqing/event-handler

[idl-generator] Add test case for event handler
:Add ARDrone pilot extension.