Updated OmniXAML.

Style includes now work - yay!

samples/XamlTestApplicationPcl/XamlTestApp.paml

@@ -2,6 +2,6 @@
         xmlns="https://github.com/perspex"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Application.Styles>
-    <!--<StyleInclude Source="resource://application/XamlTestApplicationPcl/XamlTestApplication.Button.paml"/>-->
+    <StyleInclude Source="resource://application/XamlTestApplicationPcl/XamlTestApplication.Button.paml"/>
   </Application.Styles>
 </Application>

src/Markup/Perspex.Markup.Xaml/OmniXAML

@@ -1 +1 @@
-Subproject commit 4b0aeccf9ad094782973cd76f5319e8a2d600223
+Subproject commit 81afc557c85473ba5035039c89253c1e0fe03927