changed default settings screen to quit

After boot, the default settings screen is the quit confirmation page.
This is more useful than the storage-setting, which you don't tend to
change often. Direct access to the quit confirmation page allows fast shutdown.
Use logical names for screen-modes

Introduced a class Mode with logical names for individual screens. No more
hardcoded references into lists. This will facilitate adding additional
screens as well as direct access to individual screens.

Non-functional change: reduced indentation to 2 to save some screen realestate.
Renamed variable scaled to imgSurface

The new name is a better description of what the object is.
removed items done with this version