No need to check for Qt >= 4.7. It's our minimum requirement.
factor out dedicated executable "marble-mobile" for mobile devices

Having a dedicated executable for mobile devices should ease maintainance for various reasons:
1) handling the smallscreen flag correctly is rather fragile and has lead to regressions in the past
2) allows for deeper integration into the system w/o "smart" code (determining network state, screensaver handling, hardware zoom buttons, etc.)

marble-qt looses the --smallscreen and --nosmallscreen commandline switches.

REVIEW: 112242
make RoutingWidget resizable within the QScrollArea

* fixes routing dialog getting unreadable with many way points

BUG: 322785
make DownloadRegionDialog more self-contained

* connect to and disconnect from expensive signals automatically
add degree suffices
hide NavigationFloatItem on smallscreen devices by default

* the RoutingPlugin (a float item) is used there instead