Changed how messages are retrived

I moved message retrieval into a method   `get_message`.

`get_message` takes the key of the message you are getting.  Possible keys are:
- `already_awarded`
- `confirmation`
- `too_little_text`
- `broken_rule`

I also added another section under `messages` in the config file `append_to_all_messages` which is simply appended to the end of each message.

You will notice in the config file the messages are in array form.  the `get_message` method now selects from the array at random.  So for example you can define multiple different things for DeltaBot to say and it will pick them at random.