Plethora of Examples

[alecandido]

The referee for sure has a point we are lacking examples in user manual. He had an even stronger point before we were completely lacking a user manual. We simply performed the minimal task of providing something, now we should improve a lot over that something.

Being mainly a library, we want have examples of "you run this way, you'll get this output", but we need simple examples nevertheless.

As usual, NumPy is something to look at for a good pattern to imitate.
The documentation has 4 different sections: https://numpy.org/doc/

1. API Reference: this we have (docstrings), for sure we can improve, but it is already good enough (the only one...)
2. User Guide: we attempted to provide, but there is very little
3. Getting Started: in a sense we have this and not the former one, but the truth is that we have only one out of two, with a very generic target (for us users are all the same at the moment, essentially because we have no one, so they might all be considered "Absolute Beginners")
4. Contributor's Guide: not that many candidate contributors out there, but something minimal might be useful - and something we have Benchmarks and rest of "development", together with Contributing Guidelines, so we should just need to maintain it (no need to expand at the moment, we'll cross that bridge when we come to it)

Related to #145 (examples should rely on the public interface, and, if possible, "cover" it)