See merge request !1452

See merge request !1454

See merge request !1453

See merge request !1451

See merge request !1450

See merge request !1449

- move definition back into class as gcc can deal with it just fine now
- add explicit comparison to nullptr_t so that comparison to int can be
  deprecated
- add explicit conversion to bool to give SmartRef the same semantics as
  a pointer

See merge request !1448

See merge request !1446

Closes #263

See merge request !1441

Add flake8 to the pre-commit hooks. Also add `.flake8` configuration
file to the top-level project directory.

Closes #263.

See merge request !1440

See merge request !1447

Closes #264

See merge request !1445

See merge request !1443

See merge request !1442

See merge request !1438

See merge request !1437

See merge request !1406

See merge request !1348

We do not want to implicitly convert an integer to an `EventContext` as
this would almost certainly result in an invalid event context.

Allow the comparison of properties following `SequenceSemantics` with
plain lists. Also remove the redundant `__ne__` operator which defaults
to `! __eq__` in Python3.

Closes #264.

gaudi_add_pytest is used to declare pytest tests. Each of the test
files discovered by pytest are mapped to one ctest test, to be able to
run them in parallel.

Tests are collected when ctest is invoked and/or at build time, and only
in case changes are detected in scanned files.