try to get appveyor working for py37

Author: alimanfoo

appveyor.yml

@@ -53,7 +53,7 @@ build: off
 test_script:
   - "%CMD_IN_ENV% python -m pip install -U pip setuptools wheel"
   - "%CMD_IN_ENV% python -m pip install numpy==%NUMPY_VERSION%"
+  - "%CMD_IN_ENV% python -m pip install -v --no-binary=numcodecs numcodecs==0.5.5"
   - "%CMD_IN_ENV% python -m pip install -rrequirements_dev.txt"
   - "%CMD_IN_ENV% python setup.py install"
   - "%CMD_IN_ENV% python -m pytest -v --pyargs zarr"
-  

setup.py

@@ -45,6 +45,7 @@
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
     ],
     maintainer='Alistair Miles',
     maintainer_email='[email protected]',