TWFunc::Fixup_Time_On_Boot: Will now try to read /sys/class/rtc/rtc0/since_epoch to correct time, if that fails it will try to use the ats files to correct time.

TWFunc::Set_Brightness: One single function to set brightness from both the automated functions and the gui actions. It is able to set a second brightness path if present, it will set them both the same value. The Sony Xperia ZL has 2 brightness control interfaces... It was done specifically for this model, but maybe others also benefit.

All other files changed to use these changes.

DataManager::Find_Brightness_Path: if TW_BRIGHTNESS_PATH is invalid or unset, TWRP will now attempt to find a sys control path on various known locations.

Fixed to allow previously stored settings to be applied correctly.

Change-Id: I7ca582109085dfbcb46b8de73ad031e4b7903fca