[New notification providers: Join & Telegram]

Adding the following to NotificationAgents.xml allows Telegram to work for notifications.  Not the easiest process to setup though.  First you have to send @BotFather a message '/newbot', after a few steps it sends you back your HTTP API.  Then you need to start a conversation with your bot in order to get the Chat ID to send to.  Not sure there is an easy way to integrate this into the settings page, I manually queried the API to get the chat ID.

  <Agent>
    <Name>Telegram</Name>
    <Variables>
      <Variable Help="The API key can be found [a href='https://core.telegram.org/bots/api' target='_blank'] [u]here[/u].[/a]" Desc="API key" Default="">API_KEY</Variable>
      <Variable Help="Chat ID [a href='https://core.telegram.org/bots/api' target='_blank'] [u]here[/u].[/a]" Desc="Chat ID" Default="">CHAT_ID</Variable>
      <Variable Help="Specify the fields which are included in the message body of the notification." Desc="Notification Message" Default="$DESCRIPTION">MESSAGE</Variable>
    </Variables>
    <Script>
      <![CDATA[
      #!/bin/bash
      ##########
      {0}  
      ##########
      MESSAGE=$(echo -e "$MESSAGE")
      URL=https://api.telegram.org/bot$(echo -e "$API_KEY")
      CHATID=$(echo -e "$CHAT_ID")

      curl -s -k -G \
      --data-urlencode "text=$MESSAGE" \
      $URL/sendMessage?chat_id=$CHATID
      ]]>
    </Script>
  </Agent>

Edit: While looking for something else I noticed theres another way to get the chatid.  Send '/getid' to IDBot @myidbot (https://telegram.me/myidbot) and it will reply with your chat id