Build fixes (#338)

Build/build.ps1

@@ -13,7 +13,7 @@
   $treatWarningsAsErrors = $false
   $workingName = if ($workingName) {$workingName} else {"Working"}
   $assemblyVersion = if ($assemblyVersion) {$assemblyVersion} else {$majorVersion + '.0.0'}
-  $netCliChannel = "Current"
+  $netCliChannel = "STS"
   $netCliVersion = "6.0.300"
   $nugetUrl = "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe"
   $ensureNetCliSdk = $true
@@ -27,7 +27,7 @@
   $workingDir = "$baseDir\$workingName"
 
   $nugetPath = "$buildDir\Temp\nuget.exe"
-  $vswhereVersion = "2.3.2"
+  $vswhereVersion = "3.1.7"
   $vswherePath = "$buildDir\Temp\vswhere.$vswhereVersion"
   $nunitConsoleVersion = "3.8.0"
   $nunitConsolePath = "$buildDir\Temp\NUnit.ConsoleRunner.$nunitConsoleVersion"
@@ -196,7 +196,7 @@ function EnsureNuGetPackage($packageName, $packagePath, $packageVersion)
 
 function GetMsBuildPath()
 {
-  $path = & $vswherePath\tools\vswhere.exe -latest -products * -requires Microsoft.Component.MSBuild -property installationPath
+  $path = & $vswherePath\tools\vswhere.exe -latest -prerelease -products * -requires Microsoft.Component.MSBuild -property installationPath
   if (!($path))
   {
     throw "Could not find Visual Studio install path"