1.2.1 Hidden audio sessions, new profiles, better overlay.

Updates

Added background color (in OverlaySettingsPage) to see the size of the screen.
Moving all audio related logic from MainWindow to AudioViewer (no regression allowed).
Split user profile in 2:
- UserProfile to store window properties, overlay settings and stuff like that.
- AudioProfile to store all audio related settings. -> this change was needed to have more flexibility and to clearly split responsabilities between MainWindow and AudioViewer.
Added UserProfile to save window and app related settings. AudioProfile now handles only audio related settings.
Removed app/window related settings from AudioProfile (ie IsAlwaysOnTop, WindowDisplayRect).
Moved MessageBar to the bottom to replicate Youtube's mobile app notifications (and updating animations accordingly).
Updated ToggleButton to use IInspectable (to display generic content) for OnIcon and OffIcon. It might be changed back to hstring since icon composition is not that useful.
OverlaySettingsPage now adds itself to the navigation breadcrumbs.

Fixed audio sessions being added even if another session with the same grouping parameter.
Fixed Audio session volume icon is not green when the audio session is active in vertical layout.
Fixed ToggleIconButton not properly behaving on pointer over by setting its background.

Audio sessions will need to be reloaded manually after the computer has been put to sleep or hibernation.
On some computers, pluggin/unplugging an audio jack will crash the app. The issue seems to be coming from the audio driver application.
Some I18Ned applications don't have a real name: "ms-resource:AppStoreName".