Added Visual Studio 2017 to AppVeyor config

Author: yhirose

appveyor.yml

@@ -2,10 +2,20 @@ clone_depth: 5
 
 environment:
   matrix:
-    - CMAKE_GENERATOR: "Visual Studio 14 2015"
-      CONFIGURATION: Release
-    - CMAKE_GENERATOR: "Visual Studio 14 2015 Win64"
-      CONFIGURATION: Release
+    - JOB: Visual Studio 2015
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      CMAKE_GENERATOR: "Visual Studio 14 2015"
+    - JOB: Visual Studio 2017
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      CMAKE_GENERATOR: "Visual Studio 15 2017"
+
+platform:
+  - x86
+  - x64
+
+configuration:
+  - Release
+  - Debug
 
 build_script:
   - mkdir build && cd build