Refactor process_firetext_responses
Removed the abstract ClientResponses for firetext and mmg. There is a map for each response to handle the status codes sent by each client.
Since MMG has about 20 different status code, none of which seem to be a pending state (unlike firetext that has 3 status one for pending - network delay).
For MMG status codes, look for 00 as successful, everything else is assumed to be a failure.
