Create standardized way to add new messaging services

[JohnathonNow]

Right now it is messy to add new services, such as facebook messenger. Work should be done to make this easier.

[JohnathonNow]

I'm thinking there should be an Engine class that each service inherits from. Each Engine must provide, at minimum, send_text and send_image methods. These would be used by handlers. The main application would open the decrypted configuration file, spawn an Engine for each listed service as well as pass it the configuration information, and run each Engine within a fork.