title: telegram bot send_message() hangs with HTML text
body: <p>I am new to Telegram Bot API (python telegram.ext), here is my question: I am trying to send formatted message in reply to received message. For simplicity I removed everything from the code below</p>
  
  <pre><code>    mtxt = "&lt;ul&gt;&lt;li&gt;line 1&lt;/li&gt;&lt;/ul&gt;"
      res = bot.send_message(chat_id=update.message.chat_id, text=mtxt, parse_mode='HTML')
      print(res)
  </code></pre>
  
  <p>Nothing is returned to telegram (no answer from bot) and print() never happens. If I remove 'parse_mode...' clause from the call it works.</p>
  
  <p>I must be fundamentally wrong somewhere... This is very basic staff, what is missing?</p>