Removed unneeded references.

src/Windows/Perspex.Direct2D1/Perspex.Direct2D1.csproj

@@ -50,13 +50,7 @@
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Core" />
-    <Reference Include="System.Drawing" />
-    <Reference Include="System.Windows.Forms" />
-    <Reference Include="System.Xml.Linq" />
-    <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
-    <Reference Include="System.Data" />
-    <Reference Include="System.Xml" />
     <Reference Include="System.Reactive.Core">
       <HintPath>..\..\..\packages\Rx-Core.2.2.5\lib\net45\System.Reactive.Core.dll</HintPath>
     </Reference>

src/Windows/Perspex.Win32/Perspex.Win32.csproj

@@ -40,14 +40,8 @@
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
-    <Reference Include="System.Drawing" />
     <Reference Include="System.Windows.Forms" />
-    <Reference Include="System.Xaml" />
-    <Reference Include="System.Xml.Linq" />
-    <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
-    <Reference Include="System.Data" />
-    <Reference Include="System.Xml" />
     <Reference Include="System.Reactive.Core">
       <HintPath>..\..\..\packages\Rx-Core.2.2.5\lib\net45\System.Reactive.Core.dll</HintPath>
     </Reference>