Add AppVeyor Windows CI configuration file

appveyor.yml

@@ -0,0 +1,10 @@
+build_script:
+- cd C:\
+- appveyor DownloadFile http://sourceforge.net/projects/msys2/files/Base/x86_64/msys2-base-x86_64-20150512.tar.xz/download -FileName "msys2.tar.xz"
+- 7z x msys2.tar.xz
+- 7z x msys2.tar > NUL
+- C:\msys64\usr\bin\bash -lc "pacman --needed --noconfirm -Sy bash pacman pacman-mirrors msys2-runtime"
+- C:\msys64\usr\bin\bash -lc "pacman --noconfirm -Syu"
+- C:\msys64\usr\bin\bash -lc "pacman --noconfirm -S git make"
+test_script:
+- C:\msys64\usr\bin\bash -lc "cd $APPVEYOR_BUILD_FOLDER && make -k check"