Fix virtual keyboard detection
Fix virtual keyboard detection

The window.scrollTo hack no longer works on iOS 8 so this assumes a keyboard is shown/hidden on focus/blur.

ChenMichael/trix,ChenMichael/trix,basecamp/trix,basecamp/trix,GabiGrin/trix,basecamp/trix,ChenMichael/trix,urossmolnik/trix,GabiGrin/trix,GabiGrin/trix,basecamp/trix,urossmolnik/trix,urossmolnik/trix