Now it is possible to show a CapsLock warning in a PasswordBox
Add PasswordBoxHelper to MahApps.Metro.csproj
Removal of unused using directives
Removal of blank lines
Add missing Style to MetroPasswordBox
Removed ShowCapslockWarning-DP, instead introduced CapsLockIcon-DP. This DP takes now an object that allows the developer to show any element he wants as warning icon for enabled CapsLock.

CapsLockWarningText is now of type object in order to have the same behaviour as in CapsLockIcon-DP
Adaption of xaml
Refactoring of DP for better understanding.
Oops. Forgot to revert the - to ! as default CapsLockIcon
ControlsValidationBrush is now the Foreground for "!" in PasswordBox
Merge remote-tracking branch 'MahApps-origin/master' into feature/CapsLock-for-PasswordBox

Conflicts:
	MahApps.Metro/Styles/Controls.PasswordBox.xaml
Merge pull request #1457 from xxMUROxx/feature/CapsLock-for-PasswordBox

Feature/caps lock for password box