Added initial CI config and first integration test

[dekarrin]

Patches Issue #14. Adds an integration testing framework and an initial config for Travis CI.

• Updated configfile module to read some key environment variables for config; if they exist, they will override any settings in the json.config file itself. Required for use of secrets in Drone.
• Updated Readme to show the new environment variables.
• Added minimal bot for sending commands to Discord and reading the output for use with testing MasaBot (in testerbot.py).
• Added first integration test; executes !help command and ensures that it produces proper output.
• Added script to execute integration tests locally without docker
• Added new .drone.yml file with initial configuration; currently executes all integration tests

[dekarrin]

There is nobody to review this. Unlocking restriction for admins for the time being.