docs: add badges

Author: zsquareplusc

README.rst

@@ -1,6 +1,6 @@
-==================
- pyserial-asyncio
-==================
+========================================
+ pyserial-asyncio |build-status| |docs|
+========================================
 
 Async I/O extension package for the Python Serial Port Extension for OSX, Linux, BSD
 
@@ -19,3 +19,11 @@ Latest:
 
 - Documentation: http://pyserial-asyncio.readthedocs.io/en/latest/
 - Project Homepage: https://github.com/pyserial/pyserial-asyncio
+
+
+.. |build-status| image:: https://travis-ci.org/pyserial/pyserial-asyncio.svg?branch=master
+   :target: https://travis-ci.org/pyserial/pyserial-asyncio
+   :alt: Build status
+.. |docs| image:: https://readthedocs.org/projects/pyserial-asyncio/badge/?version=latest
+   :target: http://pyserial-asyncio.readthedocs.io/
+   :alt: Documentation