Sending messages should return the msg_id or there should be a method to get last_sent_msg_id

[tuloski]

To edit a message we need to input the msg_id to modify, but there is not an "easy" way of getting the msg_id.
I think there could be two approaches:

• The sendMessage should return the id of the message
• There should be a dedicated method to retrieve the last message sent id. Something like:

int UniversalTelegramBot::getLastSentMessageId(){ return last_sent_message_id; }