[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
Init ARDrone video extension
Add ARDrone video test case
Add play()/stop() prototype
Add ability to get video stream.

Current status:
===========
  Extension with idl interface (done)
  Example (done, need update time to time)
  Extension : Able to compile/pack, need verify whether can save to test.h264 in cacheDir()

Plan:
===========
  1. Use mOption.latency() to generate seperate .h264
  2. Import mp4parser and mutex the .h264 file, and save as .mp4 in cache (the hardest one)
  3. Send "newvideoready" event when .mp4 file is ready

Command to build:
===========
gyp --depth=. all.gyp && \
ninja -C out/Default/ && make_apk.py \
--package=org.xwalk.extensions.ardrone \
--extensions="./out/Default/gen/ardrone_video/" --arch=x86 \
--manifest="./examples/ardrone_video/manifest.json" && \
adb install -r Ardrone_0.0.0.1_x86.apk

How to remote debugging:
===========
1. Apply
https://github.com/halton/crosswalk/commit/89a0d71b0094fe0c8f6bd63c092ae384504f4998
in src/xwalk
2. Rebuild xwalk_builder target
3. Pack app with make_apk.py under out/Debug/out/Debug/xwalk_app_template
4. Start app on mobile
5. Start chrome://inspect on your host PC
Able to generate two 1s videos.
Import mp4parser to use
Able to mux h264 to mp4.

But fail on second duration, we guess it is because we split on non
I-Frame packet. So we'll try to segment the P264 stream with I-Frames
instead of duration.
Export some structure to window object
Use 192.168.1.103 as server
Use 192.168.1.103 as server
Able to generate h264 by IDR-Frame and mux into mp4 file

Next: Fix why newvideoready is not responsed.