Added tests for python 3.7 and sphinx 2.0

Author: Chilipp

.travis.yml

@@ -1,16 +1,35 @@
 language: python
+# necessary for python 3.7, see https://github.com/travis-ci/travis-ci/issues/9815
+dist: xenial
+sudo: yes
 python:
   - "2.7"
   - "3.5"
   - "3.6"
+  - "3.7"
 env:
-  - SPHINX_VERSION=1.3.6
-  - SPHINX_VERSION=1.4.6
-  - SPHINX_VERSION=1.5.6
-  - SPHINX_VERSION=1.6.3
-  - SPHINX_VERSION=1.7.9
-  - SPHINX_VERSION=1.8.0
+  - SPHINX_VERSION=1.3.*
+  - SPHINX_VERSION=1.4.*
+  - SPHINX_VERSION=1.5.*
+  - SPHINX_VERSION=1.6.*
+  - SPHINX_VERSION=1.7.*
+  - SPHINX_VERSION=1.8.*
+  - SPHINX_VERSION=2.0.*
   - SPHINX_VERSION=""
+matrix:
+  exclude:
+    - python: "2.7"
+      env: SPHINX_VERSION=2.0.*
+    - python: "3.7"
+      env: SPHINX_VERSION=1.3.*
+    - python: "3.7"
+      env: SPHINX_VERSION=1.4.*
+    - python: "3.7"
+      env: SPHINX_VERSION=1.5.*
+    - python: "3.7"
+      env: SPHINX_VERSION=1.6.*
+
+
 install:
   - pip install coveralls
   # install sphinx