Viewing the source bug

Hi Subodh,

Please note that even if viewing source is disabled, CTRL+U, CTRL+SHIFT+C and CTRL+SHIFT+I still work.

Maybe some more key events could be added, like:

if (event.keyCode === 123 ||
    event.ctrlKey && event.shiftKey && event.keyCode === 73 || event.ctrlKey && event.shiftKey && event.keyCode === 67 ||
    event.ctrlKey && event.shiftKey && event.keyCode === 75)

Thanks!