IDSLab 0.3.2: a shorter README and a figures guide

Documentation only; the code and the evaluation are unchanged, and finished runs are reused.

• A shorter README: overview, quickstart for every system, guides, versions and citation.
• docs/how-it-works.md explains a run with its figures: the design, the splits, the accuracy after
  each stage, the frontier gap and the flow map.
• The project site describes the current builder, results page and fingerprints, and links the DOI.

Install

pip install idslab==0.3.2

Every change is in CHANGELOG.md. Each release is archived on Zenodo with its own DOI; 10.5281/zenodo.23435536 lists them all.