temporarily removed 3.7 testing due to Travis numpy version issue

Author: sobester

.travis.yml

@@ -2,7 +2,7 @@ language: python
 python:
   - "3.5"
   - "3.6"      # current default Python on Travis CI
-  - "3.7"
+#  - "3.7"
   - "3.8"
 #  - "3.8-dev"  # 3.8 development branch
 # command to install dependencies