all settings get applied on boot now
use integerpreference which allows negative values

this is needed for white color temperature settings, which i also added in this commit
disabled onclick listener for text feld - this didn't work properly with negative values
automated catching of text within syfs
don't apply zram settings at every 'onCreate'
added a button to apply zram settings
screen: remove settings which aren't available
fixed some typos
fixed seekbar values going out of definition by pressing + or - button