Appveyor fixes

Author: Pan

.appveyor.yml

@@ -128,4 +128,4 @@ artifacts:
   - path: "*.whl"
 
 deploy_script:
-  - IF "%APPVEYOR_REPO_TAG%" == "true"( python ci/appveyor/pypi_upload.py *.whl )
+  - python ci/appveyor/pypi_upload.py *.whl

ci/appveyor/pypi_upload.py

@@ -1,11 +1,13 @@
-from __future__ import print_function
-
 import sys
 import subprocess
 import os
 
 
 def upload_pypi(files):
+    repo_tag = os.environ['APPVEYOR_REPO_TAG']
+    if repo_tag == 'false':
+        sys.stderr.write("Not a tagged release, skipping upload" + os.linesep)
+        return
     _user, _pass = os.environ['PYPI_USER'], os.environ['PYPI_PASS']
     try:
         subprocess.check_call(['twine', 'upload', '-u', _user,