Fix appveyor build

- use chocolatey
- add extra ci command

appveyor.yml

@@ -1,22 +1,13 @@
 version: '{build}'
 os: Windows Server 2012
 install:
-  - ps: |
-      Add-Type -AssemblyName System.IO.Compression.FileSystem
-      if (!(Test-Path -Path "C:\sbt" )) {
-        (new-object System.Net.WebClient).DownloadFile(
-          'https://dl.bintray.com/sbt/native-packages/sbt/0.13.7/sbt-0.13.7.zip',
-          'C:\sbt-bin.zip'
-        )
-        [System.IO.Compression.ZipFile]::ExtractToDirectory("C:\sbt-bin.zip", "C:\sbt")
-      }
-  - cmd: SET PATH=C:\sbt\sbt\bin;%JAVA_HOME%\bin;%PATH%
+  - cmd: choco install sbt -ia "INSTALLDIR=""C:\sbt"""
+  - cmd: SET PATH=C:\sbt\bin;%JAVA_HOME%\bin;%PATH%
   - cmd: SET SBT_OPTS=-XX:MaxPermSize=2g -Xmx4g
 build_script:
   - sbt clean compile
 test_script:
-  - sbt "test-only * -- -n windows"
-  - sbt "scripted universal/dist universal/stage windows/*"
+  - sbt validateWindows
 cache:
   - C:\sbt\
   - C:\Users\appveyor\.m2

build.sbt

@@ -54,3 +54,6 @@ bintrayRepository := "sbt-plugin-releases"
 
 // scalafmt
 scalafmtConfig := Some(file(".scalafmt.conf"))
+
+// ci commands
+addCommandAlias("validateWindows", ";test-only * -- -n windows;scripted universal/dist universal/stage windows/*")