Traits version 5.2.0

This is a minor feature release, with various small updates and bugfixes.

The most notable user-facing changes are the deprecation of the Category class, which is scheduled for removal in Traits 6.0.0, and the removal of the Class, ListClass and ListInstance Trait types, which relate to old-style Python 2 classes.

Summary of changes since the 5.1.2 release:

Enhancements

• Support installation from source archives. (#528)

Fixes

• Ensure TraitListEvent.index is always an integer. (#548)
• Update the deprecated collections.MutableMapping import. (#530)
• Fix inadvertent modification of the Category base class. (#509)
• Rework version handling in setup.py. (#515)
• Don't autogenerate documentation for ViewElement. (#559)
• Ensure that all tests are unittest compatible. (#551)

Changes

• Replace occurences of deprecated AdaptsTo with Supports. (#532)
• Remove Class trait. (#520)
• Deprecate Category trait. (#510)
• Fix typos in docstrings. (#502)
• Use decorator form of classmethod. (#500)
• Remove redefinition of NullHandler. (#518)
• Add an import check helper. (#521)
• Clean up Cython tests. (#555)
• Clean up test output. (#553)

Miscellaneous

• Update EDM version on CI to version 2.0.0. (#560)
• Don't finish fast on CI. (#556)
• Use unittest to run tests in CI. (#552)
• Low-level fixes and style cleanup in etstool.py. (#550)
• Add --editable option for install, update CI commands. (#546)
• Make git commit hash available to archives. (#526)
• Fix use of non-edm envs as bootstrap envs on Windows. (#512)
• Remove edm installed package before installing from source. (#516)
• Add help text to click options. (#514)
• Various cleanups, fixes and enhancements in etstool.py. (#511)