Fix .appveyor config to match latest changes on oF master

.appveyor.yml

@@ -1,5 +1,4 @@
 version: 1.0.{build}
-os: Visual Studio 2017
 
 branches: 
   only:
@@ -10,32 +9,45 @@ environment:
     APPVEYOR_OS_NAME: windows
   matrix:
   #MSYS2 Building
-    - platform: x86
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x86
       BUILDER: MSYS2
+      CCACHE_DIR: "%APPVEYOR_BUILD_FOLDER%\\.ccache"
 
   #VisualStudio Building
-    - platform: x86
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x86
       BUILDER : VS
       BITS: 32
-    - platform: x64
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x64
       BUILDER : VS
       BITS: 64
 
 configuration: Debug
 shallow_clone: true
 clone_depth: 5
+
 init:
 - set MSYS2_PATH=c:\msys64
 - set CHERE_INVOKING=1
 - if "%BUILDER%_%PLATFORM%"=="MSYS2_x86" set MSYSTEM=MINGW32
 - if "%BUILDER%_%PLATFORM%"=="MSYS2_x64" set MSYSTEM=MINGW64
-- if "%BUILDER%"=="VS" set PATH=C:\Program Files (x86)\MSBuild\14.0\Bin;%PATH%
+- '%MSYS2_PATH%\usr\bin\bash -lc "pacman --noconfirm -S --needed unzip rsync"'
+- if "%BUILDER%"=="VS" set PATH=%ProgramFiles(x86)%\Microsoft Visual Studio\2017\Community\MSBuild\15.0\Bin;%PATH%
+
+cache:
+    - .ccache
 
 install:
 - cd ..
 - git clone --depth=1 --branch=master https://github.com/openframeworks/openFrameworks
 - call openFrameworks\scripts\ci\addons\install.cmd
 
+before_build:
+- if "%BUILDER%"=="MSYS2" (%MSYS2_PATH%\usr\bin\bash -lc "ccache -z")
+- if "%BUILDER%"=="MSYS2" (%MSYS2_PATH%\usr\bin\bash -lc "ccache -s")
+
 build_script:
 - cd %OF_PATH%
 - scripts\ci\addons\build.cmd