fix IsPressed foreground
remove boilerplate code
more boilerplate
Merge pull request #1143 from MahApps/punker76-AccentedSquareButtonStyle-issue

fix IsPressed foreground for AccentedSquareButtonStyle
minor
Added code to support changing the light and dark resources of the ThemeManager.
Removed method to change the theme base for a window.  As of right now this can not be done.  Flyouts reference the ThemeManager.LightResource and ThemeManager.DarkResource.  So if you change that on one window it will cause problems for other windows.

Changing the theme base will only work when you change it for an application until someone comes up with a way to do it for a windows.
Merge branch 'ThemeBaseAddition' of https://github.com/Tide/MahApps.Metro into ThemeBaseAddition

Conflicts:
	MahApps.Metro/ThemeManager.cs