use compiled Cython for appveyor build: we compile it anyway so that is what...

use compiled Cython for appveyor build: we compile it anyway so that is what we should test (and it speeds up the tests)

appveyor.yml

@@ -67,6 +67,7 @@ install:
 
 build: off
 build_script:
+  - "%WITH_ENV% %PYTHON%\\python.exe setup.py build --inplace"
   - "%WITH_ENV% %PYTHON%\\python.exe setup.py bdist_wheel"
 
 test: off