Previously the application was run from outside a bundle and hence did not
have an app icon - so OS X displayed the generic 'terminal' icon in the elevation
dialog. The app icon in the dock was set at runtime, but disappeared temporarily
on shutdown when the overridden app icon was replaced with the default icon.
This commit fixes the problem by detecting whether the executable is being
run from within a bundle and if not, creating a minimal app bundle in /tmp
and re-launching the updater from there.
