Add VS2017 release Appveyor build (#685)

diff --git a/scripts/appveyor.yml b/scripts/appveyor.yml
index 4e15a5b..abfb58f 100644
--- a/scripts/appveyor.yml
+++ b/scripts/appveyor.yml
@@ -4,11 +4,23 @@
 

 environment:

   matrix:

+  - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017

+    BUILD_SYSTEM: CMake

+    GENERATOR: Visual Studio 15 2017 Win64

+    CONFIG: Release

+

+  - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017

+    BUILD_SYSTEM: CMake

+    GENERATOR: Visual Studio 15 2017 Win64

+    CONFIG: Debug

+

   - BUILD_SYSTEM: CMake

     GENERATOR: Visual Studio 14 2015 Win64

+    CONFIG: Debug

 

   - BUILD_SYSTEM: CMake

     GENERATOR: Visual Studio 14 2015

+    CONFIG: Debug

 

   - BUILD_SYSTEM: Python

     PYTHON: "C:\\Python27"

@@ -38,11 +50,11 @@
     IF "%ARCH%"=="i686" (

       SET "TOOLCHAIN=i686-6.3.0-posix-dwarf-rt_v5-rev1\mingw32"

     ) ELSE (

-      SET "TOOLCHAIN=x86_64-6.3.0-posix-seh-rt_v5-rev1\mingw64"

+      SET "TOOLCHAIN=x86_64-7.3.0-posix-seh-rt_v5-rev0\mingw64"

     )

   )

 - IF "%BUILD_SYSTEM%"=="bazel" (

-    appveyor DownloadFile https://github.com/bazelbuild/bazel/releases/download/0.11.1/bazel-0.11.1-windows-x86_64.exe -FileName bazel.exe

+    appveyor DownloadFile https://github.com/bazelbuild/bazel/releases/download/0.14.1/bazel-0.14.1-windows-x86_64.exe -FileName bazel.exe

   )

 

 before_build:

@@ -56,7 +68,7 @@
 - SET "ROOT=%APPVEYOR_BUILD_FOLDER%"

 

 build_script:

-- IF "%BUILD_SYSTEM%"=="CMake" ( cmake --build . --config Debug )

+- IF "%BUILD_SYSTEM%"=="CMake" ( cmake --build . --config %CONFIG% )

 - IF "%BUILD_SYSTEM%"=="Python" ( python setup.py build_ext )

 - IF "%BUILD_SYSTEM%"=="make" (

     sh -c "make brotli" &&

@@ -75,7 +87,7 @@
   )

 

 test_script:

-- IF "%BUILD_SYSTEM%"=="CMake" ( ctest --output-on-failure --interactive-debug-mode 0 -C Debug )

+- IF "%BUILD_SYSTEM%"=="CMake" ( ctest --output-on-failure --interactive-debug-mode 0 -C %CONFIG% )

 - IF "%BUILD_SYSTEM%"=="Python" ( python setup.py test )

 - IF "%BUILD_SYSTEM%"=="make" ( sh -c "make test" )

 - IF "%BUILD_SYSTEM%"=="bazel" (