Replace Logger with loguru

[gerelef]

Lay the groundwork for #22 by replacing Logger with loguru.
Logger was introduced as an intermediary step between pure if debug print statements, and a safe & feature-complete Logger implementation.
Now, with #22 in mind, it's time to move away from it, and introduce a multiprocess-safe logger.
Some features (that already exist in our own implementation) are:

• Colours
• Easy setup
• Custom levels
• Environment Variables

And these extra, useful features:

• Exception Catching
• Verbose exceptions
• Multiprocess safety

With verbose exceptions, we'll be able to eliminate all Logger.error(...)s with a simple assert, letting the verbose exception show the values that crashed the system runtime.

This supersedes and closes #25