Add windows CI

appveyor.yml

@@ -0,0 +1,16 @@
+environment:
+  matrix:
+    - TARGET: 1.13.0-x86_64-pc-windows
+      COMPILER: gnu
+    - TARGET: 1.13.0-x86_64-pc-windows
+      COMPILER: msvc
+install:
+  - if %COMPILER%==gnu choco install -y mingw
+  - ps: Start-FileDownload "https://static.rust-lang.org/dist/rust-${env:TARGET}-${env:COMPILER}.exe" -FileName "rust-install.exe"
+  - ps: .\rust-install.exe /VERYSILENT /NORESTART /DIR="C:\rust" | Out-Null
+  - ps: $env:PATH="$env:PATH;C:\rust\bin;C:\tools\mingw64\bin"
+  - if %COMPILER%==gnu gcc -v
+  - rustc -vV
+  - cargo -vV
+build_script:
+  - cargo build