Add AppVeyor build control file

Author: jayvdb

.appveyor.yml

@@ -0,0 +1,16 @@
+# To activate, change the Appveyor settings to use `.appveyor.yml`.
+init:
+  - SET PATH=C:\\Python27\\Scripts\\;%PATH%"
+
+install:
+  - git submodule update --init --recursive
+  - python -m pip install tox
+
+build: off
+
+test_script:
+  # Avoid py35-optional, as pypi does not have lxml wheels for py35
+  - python -m tox -e "py35-base,{py27,py33,py34}-{base,optional}"
+
+after_test:
+  - python debug-info.py