invoke setup.py build on appveyor

for better output

Author: minrk

appveyor.yml

@@ -20,6 +20,7 @@ install:
   - cmd: conda config --add channels conda-forge
   #- cmd: conda update --yes --quiet conda
   - cmd: conda install -y pyzmq tornado jupyter_client nbformat nbconvert ipykernel pip nodejs nose
+  - cmd: python setup.py build
   - cmd: pip install .[test]
 
 test_script: