Microsoft.UI.Xaml v2.1.190319001-prerelease

https://www.nuget.org/packages/Microsoft.UI.Xaml/2.1.190319001-prerelease

Features:

• Down-level styles from rs5 or 19h1 to rs1: One style per control (816a72be by licanhua, pr #315)

Notable bug fixes:

• Fixed navview hamburger button HC (56964b69 by ojhad, pr #431)
• Fix TreeViewItem left padding (4ececc30 by kaiguo, pr #438)
• TeachingTip API renames (bdc806d9 by StephenLPeters, pr #409)
• SplitButton - add TemplateBinding for content alignment properties (520397de by jevansaks, pr #401)
• Change RadioMenuFlyoutItem glyph (db41b310 by teaP, pr #399)
• Fix bad vsm setter for IconBorder.Child (2b620982 by StephenLPeters, pr #364)
• NavigationView header and hamburger button overlap fix (42eca6ad by ojhad, pr #332)