Add CI for Windows (#72)

Author: an-tao

.appveyor.yml

@@ -0,0 +1,26 @@
+version: 1.0.0.{build}
+image: Visual Studio 2019
+configuration:
+- Release
+- Debug
+
+environment:
+  matrix:
+    - GENERATOR: Visual Studio 16 2019
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ARCH: Win32
+      
+    - GENERATOR: Visual Studio 16 2019
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      ARCH: x64
+      
+init: []
+
+before_build:
+- md build
+- cd build
+- cmake --config "%CONFIGURATION%" -G "%GENERATOR%" ..
+build_script:
+- cmake --build . --config "%CONFIGURATION%"
+build:
+  verbosity: minimal

README.md

@@ -1,6 +1,7 @@
 # TRANTOR
 
 [![Build Status](https://travis-ci.org/an-tao/trantor.svg?branch=master)](https://travis-ci.org/an-tao/trantor)
+[![Build status](https://ci.appveyor.com/api/projects/status/yn8xunsubn37pi1u/branch/master?svg=true)](https://ci.appveyor.com/project/an-tao/trantor/branch/master)
 [![Language grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/an-tao/trantor.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/an-tao/trantor/context:cpp)
 
 A non-blocking I/O cross-platform TCP network library, using C++14.