Several documentation enhancements and build warnings fixes

- Made the documentation even more friendly towards newbies.
- Eased the usage of methods like get history which now set
  a default empty message for message actions and vice versa.
- Fixed some docstring documentations too.
- Updated the old normal docs/ to link back and forth RTD.
- Fixed the version of the documentation, now auto-loaded.

readthedocs/extra/examples/chats-and-channels.rst

@@ -3,6 +3,11 @@ Working with Chats and Channels
 ===============================
 
 
+.. note::
+
+    These examples assume you have read :ref:`accessing-the-full-api`.
+
+
 Joining a chat or channel
 *************************