style formatting
use ControlsDisabledBrush

for disabled checkbox and radiobutton
fix for ShowIconOnTitleBar="False"
fix flyout stuff
revert using ControlsDisabledBrush

for CheckBox and RadioButton
revert resetting SemiTransparentWhiteColor

it's not necessary
remove unnecessary brush
Merge pull request #695 from MahApps/694-punker76-WindowCommands-TitleBar-issues

Fixes for issue #694