install ninja using Chocolatey

appveyor.yml

@@ -10,6 +10,8 @@ test: off
 cache:
 - work\git -> ci\appveyor.ps1
 - work\install -> ci\appveyor.ps1
+- C:\ProgramData\chocolatey\bin -> ci\appveyor.ps1
+- C:\ProgramData\chocolatey\lib -> ci\appveyor.ps1
 
 environment:
     matrix:

ci/appveyor.ps1

@@ -57,9 +57,7 @@ if ( !(Test-Path "$env:APPVEYOR_BUILD_FOLDER\work\install" ) )
     mkdir $env:APPVEYOR_BUILD_FOLDER\work\install
     mkdir $env:APPVEYOR_BUILD_FOLDER\work\git
     
-    Start-FileDownload https://github.com/martine/ninja/releases/download/v1.6.0/ninja-win.zip
-    7z e ninja-win.zip -o$INSTALL_DIR
-    rm  ninja-win.zip
+    cinst ninja
     
     cd $env:APPVEYOR_BUILD_FOLDER\work\git
     git clone -q git://anongit.kde.org/extra-cmake-modules.git