Reflowable Layout

1. Fixed Bug that sometimes app crashed when back button is pressed.
2. Fixed Bug that Video inside iframe tag is not rendered properly.
3. Fixed Bug that Video will not appear (but sound is audible) for some devices.
4. 3 events are added in ClickListener.

public interface ClickListener {
/**
* called when user taps on iframe
* @param x x coodination at click point.
* @param y y coodination at click point.
* @param src the source of iframe
*/
void onIFrameClicked(int x,int y,String src);

/**
* called when video tag is clicked
* @param x x coodination at click point.
* @param y y coodination at click point.
* @param src the source of media
*/
void onVideoClicked(int x,int y,String src);

/**
* called when video tag is clicked
* @param x x coodination at click point.
* @param y y coodination at click point.
* @param src the source of media
*/
void onAudioClicked(int x,int y,String src);
}