Reverting back to older numpy

.travis.yml

@@ -10,7 +10,7 @@ python:
 # https://stackoverflow.com/a/48185032
 before_install:
 # Currently there is an issue with 1.16 and SCS
- - pip install -U --only-binary=numpy, scipy numpy==1.16.2
+ - pip install -U --only-binary=numpy, scipy numpy==1.15.4
 
 install:
  - pip install pytest