[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.
Merge pull request #16 from legendlee1314/ardrone_pilot_new

Add ARDrone pilot extension.
[ARDrone] Workaround for a new issue from gyp

Use distinct string to avoid conflict in gyp cache.

Details of the issue:
http://code.google.com/p/gyp/issues/detail?id=112