Update badges

- Update version numbers
- Use badgen.net instead of shields.io
- Remove badges from the docs (they're only present in the README)

README.rst

@@ -1,23 +1,27 @@
 ``fbchat``: Facebook Chat (Messenger) for Python
 ================================================
 
-.. image:: https://img.shields.io/badge/license-BSD-blue.svg
+.. image:: https://badgen.net/pypi/license/fbchat
     :target: https://github.com/carpedm20/fbchat/tree/master/LICENSE
     :alt: License: BSD 3-Clause
 
-.. image:: https://img.shields.io/badge/python-2.7%2C%203.4%2C%203.5%2C%203.6%203.7%20pypy-blue.svg
+.. image:: https://badgen.net/badge/python/3.5,3.6,3.7,3.8,pypy?list=|
     :target: https://pypi.python.org/pypi/fbchat
-    :alt: Supported python versions: 2.7, 3.4, 3.5, 3.6, 3.7 and pypy
+    :alt: Supported python versions: 3.5, 3.6, 3.7, 3.8 and pypy
 
-.. image:: https://readthedocs.org/projects/fbchat/badge/?version=latest
+.. image:: https://badgen.net/pypi/v/fbchat
+    :target: https://pypi.python.org/pypi/fbchat
+    :alt: Project version
+
+.. image:: https://readthedocs.org/projects/fbchat/badge/?version=stable
     :target: https://fbchat.readthedocs.io
     :alt: Documentation
 
-.. image:: https://travis-ci.org/carpedm20/fbchat.svg?branch=master
+.. image:: https://badgen.net/travis/carpedm20/fbchat
     :target: https://travis-ci.org/carpedm20/fbchat
     :alt: Travis CI
 
-.. image:: https://img.shields.io/badge/code%20style-black-000000.svg
+.. image:: https://badgen.net/badge/code%20style/black/black
     :target: https://github.com/ambv/black
     :alt: Code style