#712 Advanced build matrix [skip travis]

Signed-off-by: Uilian Ries <uilianries@gmail.com>

appveyor.yml

@@ -481,6 +481,15 @@ for:
     matrix:
       only:
         - configuration: Debug
+      - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+        CONAN_VISUAL_VERSIONS: 12
+        PYTHON: "C:\\Python37"
+      - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+        CONAN_VISUAL_VERSIONS: 14
+        PYTHON: "C:\\Python37"
+      - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+        CONAN_VISUAL_VERSIONS: 15
+        PYTHON: "C:\\Python37"
     install:
       - set PATH=%PATH%;%PYTHON%/Scripts/
       - pip.exe install conan conan_package_tools