Scale the 'body' element for 1280*720 screen

The view of the current web page is shown in half of screen.
Set the scale factor.
Merge pull request #4 from yongsheng/master

Scale the 'body' element for 1280*720 screen
Fixing some errors in css, and one in the js in index.html
Scaling to fullscreen, ignoring aspect ratio.
Switch scaling to a solution that maintains aspect ratio and rotates portrait to look like landscape.