Changed NuGet.targets to use a slash instead of a space following the…

… SolutionDir

This allows it to work with the latest version of NuGet.
Since some packages that HearThis needs require a more recent version of NuGet, I also added a conditional command to update nuget to the latest version if it already exists.
(See NuGet/Home#7657 for background)

.nuget/NuGet.targets

@@ -19,7 +19,6 @@
 	<ItemGroup Condition=" '$(PackageSources)' == '' ">
 		<!-- Package sources used to restore packages. By default, registered sources under %APPDATA%\NuGet\NuGet.Config will be used -->
 		<!-- The official NuGet package source (https://nuget.org/api/v2/) will be excluded if package sources are specified and it does not appear in the list -->
-
 	  <PackageSource Include="https://nuget.org/api/v2/" />
 	  <PackageSource Include="http://build.palaso.org/guestAuth/app/nuget/v1/FeedService.svc/" />
 	</ItemGroup>
@@ -44,7 +43,7 @@
 		<NonInteractiveSwitch Condition=" '$(VisualStudioVersion)' != '' AND '$(OS)' == 'Windows_NT' ">-NonInteractive</NonInteractiveSwitch>
 
 		<!-- Commands -->
-		<RestoreCommand>$(NuGetCommand) install "$(PackagesConfig)" -source "$(PackageSources)"  $(NonInteractiveSwitch) $(RequireConsentSwitch) -solutionDirectory "$(SolutionDir) " </RestoreCommand>
+		<RestoreCommand>$(NuGetCommand) install "$(PackagesConfig)" -source "$(PackageSources)"  $(NonInteractiveSwitch) $(RequireConsentSwitch) -solutionDirectory "$(SolutionDir)/" </RestoreCommand>
 		<BuildCommand>$(NuGetCommand) pack "$(ProjectPath)" -Properties Configuration=$(Configuration) $(NonInteractiveSwitch) -OutputDirectory "$(PackageOutputDir)" -symbols</BuildCommand>
 
 		<!-- We need to ensure packages are restored prior to assembly resolve -->
@@ -71,10 +70,11 @@
 		<MsBuild Targets="_DownloadNuGet" Projects="$(MSBuildThisFileFullPath)" Properties="Configuration=NOT_IMPORTANT;DownloadNuGetExe=$(DownloadNuGetExe)" />
 	</Target>
 
-	<Target Name="_DownloadNuGet" Condition=" '$(DownloadNuGetExe)' == 'true' AND !Exists('$(NuGetExePath)')">
-		<DownloadNuGet OutputFilename="$(NuGetExePath)" Condition="'$(OS)' == 'Windows_NT'" />
+	<Target Name="_DownloadNuGet" Condition=" '$(DownloadNuGetExe)' == 'true'">
+		<Exec Command="$(NuGetExePath) update -self" Condition="Exists('$(NuGetExePath)')" />
+		<DownloadNuGet OutputFilename="$(NuGetExePath)" Condition="'$(OS)' == 'Windows_NT' AND !Exists('$(NuGetExePath)')" />
 		<Exec Command="wget https://dist.nuget.org/win-x86-commandline/latest/nuget.exe" WorkingDirectory="$(NuGetToolsPath)"
-			Condition="'$(OS)' != 'Windows_NT'" />
+			Condition="'$(OS)' != 'Windows_NT' AND !Exists('$(NuGetExePath)')" />
 	</Target>
 
 	<Target Name="RestorePackages" DependsOnTargets="CheckPrerequisites">

src/HearThis/HearThis.csproj

@@ -17,8 +17,6 @@
     </TargetFrameworkProfile>
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
     <RestorePackages>true</RestorePackages>
-    <NuGetPackageImportStamp>
-    </NuGetPackageImportStamp>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
     <PlatformTarget>x86</PlatformTarget>

src/HearThisTests/HearThisTests.csproj

@@ -18,8 +18,6 @@
     </TargetFrameworkProfile>
     <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
     <RestorePackages>true</RestorePackages>
-    <NuGetPackageImportStamp>
-    </NuGetPackageImportStamp>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>