Supply missing WindowsTargetPlatformVersion setting that vs2017 insists be there

Add some NuGet droppings to .gitignore

Conflicts:
	.gitignore

Author: eburkitt

.gitignore

@@ -66,4 +66,6 @@ Intermediate/
 .vs/
 # Ignore cmake building directories
 build.*/
-docs/
+docs/
+# ignore NuGet artifacts
+.nuget/

Release/src/build/vs14.xp/casablanca140.xp.vcxproj

@@ -13,6 +13,7 @@
     <WinRTProject>false</WinRTProject>
     <TargetXP>true</TargetXP>
     <ProjectName>cpprestsdk140.xp</ProjectName>
+    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
   </PropertyGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), build.root))\Build\Config.Definitions.props" />
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
@@ -42,7 +43,6 @@
   </PropertyGroup>
   <PropertyGroup>
     <TargetName>$(CppRestBaseFileName)140$(DebugFileSuffix)_xp_$(CppRestSDKVersionFileSuffix)</TargetName>
-    <NuGetPackageImportStamp>eec97f90</NuGetPackageImportStamp>
   </PropertyGroup>
   <ItemGroup>
     <None Include="packages.config">