Great Work.. Bro..
i would a few suggestions

1) use volume-rocker/up-down-key for scroling..
2) when we are at the bottom of page pressing down-key/volume-rocker once again for next page..(same goes for previous page)
3) NIGHT MODE will be highly appreciated(you already made it in settings)
4) portrait mode can still be achieved with keyboard open "PLEASE DONT DISABLE IT, ITS GOOD IF WE CANT TOUCH THE TEXT FOR ANY REASON"
5) FULLSCREEN MODE..