remove build.cmd

Author: willmcgugan

appveyor.yml

@@ -31,7 +31,7 @@ test_script:
   # Note that you must use the environment variable %PYTHON% to refer to
   # the interpreter you're using - Appveyor does not do anything special
   # to put the Python version you want to use on PATH.
-  - "build.cmd %PYTHON%\\python.exe -m tox"
+  - "%PYTHON%\\python.exe -m tox"
 #after_test:
 # This step builds your wheels.
 # Again, you only need build.cmd if you're building C extensions for