Sensible Defaults as Shared Settings

Previously global flags #10 were causing some issues on imports.

In the process of refactoring this project there are some pieces of code that could use sensible defaults.
Most cases warrant moving the global variables into constructors `__init__()`, and having sensible defaults defined in a top level `settings.py` with some documentation.

If there will be a need of more fragmented shared settings, then per-library `settings.py` file should suffice.