[bb10] [build] Fix Linker issue on Mac

This commit make it possible for us to cross compile plexydesk for bb10
on Mac

refs #280
[bb10] Fix BB::Application instance crashing with PlexyDesk::Config

Avoid using QDesktopWidget in PlexyConfig this results in a Crash when
we run plexydesk inside BB::Application loop.

refs #280
[bb10] Remove all the Qt code and Add Cascade stuff

Replace the Qt Applicaiton loop with Cascade applicaiton loop

refs #280