travis: Test building docs

Author: auscompgeek

.travis.yml

@@ -3,7 +3,11 @@ language: python
 services:
 - docker
 
+install:
+- pip install sphinx sphinx-rtd-theme
+
 script:
+- make -C docs html
 - ./build_exe.sh
 
 deploy:
@@ -27,4 +31,4 @@ notifications:
     - https://webhooks.gitter.im/e/2fb1c026e64fdd70d27b
     on_success: change
     on_failure: always
-    on_start: never
+    on_start: never