Test python3.7 (#89)

* Test python3.7

* Try without travis addons

Author: mfeurer

.travis.yml

@@ -1,8 +1,12 @@
 language: python
-python:
-  - "3.4"
-  - "3.5"
-  - "3.6"
+matrix:
+  include:
+    - python: 3.4
+    - python: 3.5
+    - python: 3.6
+    - python: 3.7
+      dist: xenial
+      sudo: required
 
 
 cache:
@@ -15,15 +19,6 @@ sudo: false
 before_cache:
   - rm -f $HOME/.cache/pip/log/debug.log
 
-# command to install dependencies
-addons:
-  apt:
-    packages:
-    - libatlas-dev
-    - liblapack-dev
-    - libatlas-base-dev
-    - gfortran
-
 install:
   - pip install pip --upgrade
   - pip install numpy