Resolve "Allow items in menu bar to be automatically opened in new tab"

Closes #608

See merge request !892

Resolve "Add avatar field to Person and Group"

Closes #560

See merge request !809

Resolve "Rethink mobile tables"

Closes #505

See merge request !890

# Conflicts:
#   CHANGELOG.rst

Resolve "Send emails for celery tasks with status "FAILURE""

Closes #312

See merge request !877

Fix migrations

See merge request !891

Resolve "Firefox app icon not updated"

Closes #558

See merge request !831

Resolve "Correctly honour is_active flag on persons"

Closes #69

See merge request !883

# Conflicts:
#   CHANGELOG.rst

Add docs about social accounts

See merge request !889

Rewrite socialaccount login template

See merge request !886

Resolve "OpenID Login process: Visually indicate login flow"

Closes #464

See merge request !885

Fix wheel to not include non-package files

See merge request !887

Merge branch '601-attributeerror-at-data_check-nonetype-object-has-no-attribute-_meta-ticket-75816' into 'master'

Resolve "AttributeError at /data_check/' · NoneType' object has no attribute '_meta' [Ticket#75816]"

Closes #601

See merge request !882

Merge branch 'master' into 601-attributeerror-at-data_check-nonetype-object-has-no-attribute-_meta-ticket-75816