Initial hack on the Flyout themes
After a second thought, this naming is simpler
Fix the various themes
Fix Net45 build
Fix the accent brushes
Fix the colors again, yay
Fix accidentally commited demo
Foregrounds were missing again
Press a few more examples into the flyout demo
Fix the flyout width
Add a demo for the adaptive flyout
Adapt the window buttons to the flyout theme

This doesn't work for custom window commands yet
Fix the custom window command foreground brush when opening a flyout with the light theme

This also unifies some of the behavior of the CleanWindowStyle
Handle Flyout themes in the CleanWindow too
Handle the dark theme properly
Write some words in the release notes regarding the flyout themes
PR reference, blah
Merge pull request #941 from MahApps/flyout-theme

Flyout themes