Required fixes:
- CallbackQuery is now comparable.
- Message.effective_attachment, Message.photo,
Message.new_chat_members, Message.new_chat_photo &
Game.text_entitties semantic fixes - when they are not defined,
return an empty list.
- Docstring fix to Update class.
While not stickily necessary for most classes (since user isn't directly creating them) it still unifies our approach.
However for some like ReplyKeyboardHide where users are making the classes themselves it should improve IDE autocomplete support.
* bot.py: add create_references method
* create bot reference in webhook handler, use create_references on new updates
* message.py: implement reply_text
* echobot2.py: use Message.reply_text
* fix create_references in webhook handler
* add some more instance methods
* Chat.kick_member and unban_member
* bot.py: Create bot references in outgoing messages
* add tests for everything testable
* test_updater.py: add create_references method to MockBot
* remove Bot.create_references and refactor TelegramObject.de_json to take the additional parameter bot
* List bot as named kwarg where used
* file.py: Use Bot.request property instead of Bot._request attr
