Cleans up tests a little bit

[ralexmatthews]

Description

This adds support for environment variables in the .env when running tests, and adds a mocharc.json file to hold the mocha commands.

I just added a requirement on the dotenv package, the standard Node.js package for reading .env files, and moved the command line flags from the package.json into a mocharc.json file.

This solves the issues of like:

• Its been months since I worked on this, what were my API keys again?
• I need to pass 3 env variables to the tests, and now my command is like 3 lines tall in the terminal

Also fixes the repl command, since that was pointing to a file that didn't exist.

Testing

This is a change to the testing suite itself, so if the tests pass, this is tested, I guess?

Pull Request Type

Please select the option(s) that are relevant to this PR.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement (fixing a typo, updating readme, renaming a variable name, etc)