Add Windows CI via AppVeyor

appveyor.yml

+# Notes:
+#   - Minimal appveyor.yml file is an empty file. All sections are optional.
+#   - Indent each level of configuration with 2 spaces. Do not use tabs!
+#   - All section names are case-sensitive.
+#   - Section names should be unique on each level.
+
+#---------------------------------#
+#      general configuration      #
+#---------------------------------#
+
+# version format
+#version: 0.10.{build}
+
+# branches to build
+branches:
+  # blacklist
+  except:
+    - gh-pages
+
+# Do not build on tags (GitHub only)
+skip_tags: true
+
+#---------------------------------#
+#    environment configuration    #
+#---------------------------------#
+
+os: Windows Server 2012
+
+# scripts that run after cloning repository
+install:
+  # install Win-Flex-Bison
+  #- cmd: cinst winflexbison -y
+
+#---------------------------------#
+#       build configuration       #
+#---------------------------------#
+
+# scripts to run before build
+before_build:
+  - cmd: cmake .
+
+# scripts to run *after* solution is built and *before* automatic packaging occurs (web apps, NuGet packages, Azure Cloud Services)
+# before_package:
+
+# scripts to run after build
+# after_build:
+
+# to run your custom scripts instead of automatic MSBuild
+build_script:
+  - cmd: cmake --build .
+
+# to disable automatic builds
+# build: off