Python interface for calling the C++ code

[misharash]

Defining change: python function wrapper that launches the main computation.
Currently realized by writing the temporary files and invoking the appropriate pre-built binary on command line automatically for the user.
Worth a major version (3.0) in my opinion.

Also restructured most of the scripts, in each one wrapped the full procedure as well as its reusable parts into functions.

TODO:

• test;
• update the docs,
  • rewrite the tutorials into Jupyter notebooks;
• form an installable Python package;