Able to generate h264 by IDR-Frame and mux into mp4 file

Next: Fix why newvideoready is not responsed.
Able to play videos

Next: the video is too short, need slow down.
Now the video play well ~10 fps

Some minor issues:
* Ocationally get black screen
* Some times core dump when mux

Next:
* Move common js from webapp into extension
* Try to use Android android.media.MediaMuxer for API level 18
Enhance play() to accept a canvas id.

Old way, web app developer need offer one video element and one canvas
element, as well as the JS code related with updateCanvas.

We move those common code into extension js, and change play() to
accept a Canvas element id. Thus, web app developer can write very
simple code as examples/ardrone_video/index.html with only one canvas
element. The video element will be added as hidden on demand.
Add some more callbacks