Fix description content type

.travis.yml

@@ -14,7 +14,8 @@ before_script:
   # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
   - flake8 manimlib/ --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
 script:
-  - true  # add other tests here
+  - python setup.py test
+  - python setup.py bdist_wheel
 deploy:
   provider: pypi
   user: swegener

setup.cfg

@@ -4,7 +4,7 @@ author = Grant Sanderson
 author-email= grant@3blue1brown.com
 summary = Animation engine for explanatory math videos
 description-file = README.md
-description-content-type = text/x-md; charset=UTF-8
+description-content-type = text/markdown; charset=UTF-8
 home-page = https://github.com/3b1b/manim
 project_urls =
     Bug Tracker = https://github.com/3b1b/manim/issues