Visual(?): Change Master Password screen is very broken in beta 34

There are a bunch of visual issues with the screen for changing the master password in beta 34, but probably the biggest issue is the lack of a back button. You can still get out of the screen by swiping back, but a back button might be a good idea since that's more functional than aesthetic :P

Other visual issues include misaligned password entry field and weird flashing sections of background as the page comes into view.