Add AppVeyor support.

appveyor.yml

@@ -0,0 +1,28 @@
+environment:
+  matrix:
+    - GENERATOR: Visual Studio 14 2015 Win64
+    - GENERATOR: Visual Studio 14 2015
+    - GENERATOR: Visual Studio 12 2013 Win64
+    # - GENERATOR: Visual Studio 11 2012
+    # - GENERATOR: Visual Studio 10 2010 Win64
+    # - GENERATOR: Visual Studio 9 2008
+
+branches:
+  except:
+    - /^(wip\/)?(travis|osx|ipp)(\-.+)?$/
+    - /^master$/
+
+before_build:
+  - ps: |
+      git submodule -q update --init --recursive
+      mkdir build
+      cd build
+      cmake -G "$env:GENERATOR" ..
+
+build_script:
+  - ps: |
+      cmake --build . --config Debug
+
+# test_script:
+#   - ps: |
+#       ctest --output-on-failure --interactive-debug-mode 0 -C Debug -V