Try and set up appveyor for building Vim

.appveyor.yml

@@ -0,0 +1,13 @@
+---
+init:
+  # Build Vim
+  - cd C:\
+  - git clone https://github.com/vim/vim
+  - cd vim
+  - git checkout v8.0.0027
+  - cd src
+  - 'nmake -f Make_mvc2.mak CPU=AMD64 OLE=no GUI=no IME=yes MBYTE=yes
+    ICONV=yes DEBUG=no FEATURES=NORMAL'
+
+test_script:
+  - echo hello world