Add Windows Phone 8.1 target

src/Microsoft.VisualStudio.Validation.Portable/Microsoft.VisualStudio.Validation.Portable.csproj

@@ -16,7 +16,7 @@
     <DefaultLanguage>en-US</DefaultLanguage>
     <FileAlignment>512</FileAlignment>
     <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
-    <TargetFrameworkProfile>Profile44</TargetFrameworkProfile>
+    <TargetFrameworkProfile>Profile151</TargetFrameworkProfile>
     <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
     <OutputPath>$(OutputPath)$(MSBuildProjectName)\</OutputPath>
   </PropertyGroup>