HW9&10: Details in description.

1. Auto resize to fit the browser.
2. Auto change to landscape if the browser's width is less than the
game's, in another word it will only effects in mobile phone. (Tested in
iPhone 5s...)
3. Change the sound of capture piece to a more suitable one, except for
the cannon which still booooms...

Known bugs:
1. Due to the bug of gwt-dnd, drag and drop won't work... (Yet it is not
deleted)
2. There's no sound in mobile device.
3. A message will popup during the first move (possiblely caused by the
sound...), yet the move is valid and everything back to normal after...

Without emulator: (Tested in iPhone 5s...)
http://2-8.banqi-smg.appspot.com/
With emulator:
http://2-9.banqi-smg.appspot.com/