Class to store the botan_token, message_wrapper for python-telegram-bot.

Hello,

I created a class to store the botan_token for further use. It's now possible to initialize this class at the beginning of the program and use it in the whole program, without entering the botan_token again.

I also added the decorator for functions that handle python-telegram-bot updates. Example code for that:

`from botan import Botan
from telegram.ext import Updater, MessageHandler

updater = Updater("telegram_token")
botan = Botan("botan_token")

@botan.track_message
def echo(bot, update):
update.message.reply_text(update.message.text)

updater.dispatcher.add_handler(...)
...`

I hope I can help!

Best regards,

Jannik