Add RTD doc build, and move to after_success.

Author: daspecster

.travis.yml

@@ -12,10 +12,11 @@ script:
   - tox -e cover
   - tox -e system-tests
   - tox -e system-tests3
-  - tox -e json-docs
 
 after_success:
   - tox -e coveralls
+  - tox -e docs
+  - tox -e json-docs
 
 deploy:
   provider: pypi