set default value of  document.hidden

I think document.hidden need default value "false".

Because  sometimes I need to check it's value by "===" in a function and the function will be called as soon as the app start-up.
Merge pull request #272 from finscn/patch-3

set default value of  document.hidden
Cosmetics.fix:"mixed tab&space" and "ending space"

Cosmetics.fix:"mixed tab&space" and "ending space"
Cosmetics
Merge pull request #273 from finscn/patch-4

Cosmetics.fix:"mixed tab&space" and "ending space"
Added ejecta.allowSleepMode; close #270
update