set backlight after sunset & test notification

1. light backlight only between sunrise and sunset
2. add menu for test notificaiton
set backlight by sunset

1. option to turn on backlight only if after sunset
2. add menu to test notifcation
Merge branch 'master' of https://github.com/chaimt/PebbleNotificationCenter-Android
change backlight from checkbox to list

list: none, backlight, aftersunset
Merge pull request #13 from chaimt/master

option for backlight after sunset