Added code to make the Expander control have a disabled look.
Added mouse over and pressed effect to the expander toggle button.
Fixes #1270
Merge pull request #1267 from Tide/ExpanderDisabledFix

Fixes #1266
expander style xaml formatting
use BackgroundToForegroundConverter in expander style
GroupBoxHeaderForeground default to null like expander (can be overwritten)
set version to 0.13.0.0
Update 0.13.0.md
Merge pull request #1277 from Tide/1270.DialogAccentFix

Fixes #1270
xaml formatting for dialog styles
set mahapps to 0.13.1.0 and resources to 0.2.1.0
0.13.1 release notes
Wording
Now Splitbutton popup closes even when no selection changed event fire (fixes #1295)
Merge pull request #1296 from QuantumDeveloper/Split_DropDownButtons

Now Splitbutton popup closes even when no selection changed event fire (...