Automatically install both the 'current' and 'preview' SDKs when building in Appveyor

Author: SteveSandersonMS

appveyor.yml

@@ -1,5 +1,20 @@
 init:
   - git config --global core.autocrlf true
+install:
+   # .NET Core SDK binaries
+   # Download .NET Core SDK and add to PATH
+   - ps: $urlCurrent = "https://go.microsoft.com/fwlink/?LinkID=834991"
+   - ps: $urlPreview = "https://dotnetcli.blob.core.windows.net/dotnet/Sdk/rel-1.0.0/dotnet-dev-win-x64.latest.zip"
+   - ps: $env:DOTNET_INSTALL_DIR = "$pwd\.dotnetsdk"
+   - ps: mkdir $env:DOTNET_INSTALL_DIR -Force | Out-Null
+   - ps: $tempFileCurrent = [System.IO.Path]::GetTempFileName()
+   - ps: $tempFilePreview = [System.IO.Path]::GetTempFileName()
+   - ps: (New-Object System.Net.WebClient).DownloadFile($urlCurrent, $tempFileCurrent)
+   - ps: (New-Object System.Net.WebClient).DownloadFile($urlPreview, $tempFilePreview)
+   - ps: Add-Type -AssemblyName System.IO.Compression.FileSystem; [System.IO.Compression.ZipFile]::ExtractToDirectory($tempFileCurrent, $env:DOTNET_INSTALL_DIR)
+   - ps: Add-Type -AssemblyName System.IO.Compression.FileSystem; [System.IO.Compression.ZipFile]::ExtractToDirectory($tempFilePreview, $env:DOTNET_INSTALL_DIR + "preview")
+   - ps: Move-Item "${env:DOTNET_INSTALL_DIR}preview\sdk\*" "${env:DOTNET_INSTALL_DIR}\sdk\"
+   - ps: $env:Path = "$env:DOTNET_INSTALL_DIR;$env:Path"
 build_script:
   - npm install -g npm@^3.0.0
   - npm --prefix templates/package-builder install