Remove now-unneeded assembly references.

samples/BindingTest/MainWindow.xaml

@@ -1,6 +1,6 @@
 <Window xmlns="https://github.com/avaloniaui"
-        xmlns:vm="clr-namespace:BindingTest.ViewModels;assembly=BindingTest"
-        xmlns:local="clr-namespace:BindingTest;assembly=BindingTest">
+        xmlns:vm="clr-namespace:BindingTest.ViewModels"
+        xmlns:local="clr-namespace:BindingTest">
   <Window.Styles>
     <Style Selector="TextBlock.h1">
       <Setter Property="FontSize" Value="18"/>

samples/ControlCatalog/DecoratedWindow.xaml

@@ -1,7 +1,7 @@
 <Window xmlns="https://github.com/avaloniaui" MinWidth="500" MinHeight="300"
         Title="Avalonia Control Gallery"
-        Icon="resm:ControlCatalog.Assets.test_icon.ico?assembly=ControlCatalog"
-        xmlns:local="clr-namespace:ControlCatalog;assembly=ControlCatalog" HasSystemDecorations="False">
+        Icon="resm:ControlCatalog.Assets.test_icon.ico"
+        xmlns:local="clr-namespace:ControlCatalog" HasSystemDecorations="False">
     <Grid RowDefinitions="5,*,5" ColumnDefinitions="5,*,5">
         <DockPanel  Grid.Column="1"  Grid.Row="1" >
             <Grid Name="TitleBar" Background="LightBlue" DockPanel.Dock="Top" ColumnDefinitions="Auto,*,Auto">

samples/ControlCatalog/MainView.xaml

@@ -1,5 +1,5 @@
 <UserControl xmlns="https://github.com/avaloniaui"
-        xmlns:pages="clr-namespace:ControlCatalog.Pages;assembly=ControlCatalog"
+        xmlns:pages="clr-namespace:ControlCatalog.Pages"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <TabControl Classes="sidebar" Name="Sidebar">
     <TabControl.Transition>

samples/RenderTest/MainWindow.xaml

@@ -1,6 +1,6 @@
 <Window xmlns="https://github.com/avaloniaui"
         Title="Avalonia Render Test"
-        xmlns:pages="clr-namespace:RenderTest.Pages;assembly=RenderTest">
+        xmlns:pages="clr-namespace:RenderTest.Pages">
   <DockPanel>
     <Menu DockPanel.Dock="Top">
       <MenuItem Header="Rendering">

src/Avalonia.Diagnostics/Views/TreePageView.xaml

@@ -1,5 +1,5 @@
 <UserControl xmlns="https://github.com/avaloniaui"
-             xmlns:vm="clr-namespace:Avalonia.Diagnostics.ViewModels;assembly=Avalonia.Diagnostics">
+             xmlns:vm="clr-namespace:Avalonia.Diagnostics.ViewModels">
   <Grid ColumnDefinitions="*,4,3*">    
     <TreeView Name="tree" Items="{Binding Nodes}" SelectedItem="{Binding SelectedNode, Mode=TwoWay}">
       <TreeView.DataTemplates>