0.7.0

• Properly display chained exceptions (PEP-3134).
• Rewrite celery integration to monkeypatch instead of using signals due to
  bugs in Celery 3's signal handling. The Celery scope is also now available in
  prerun and postrun signals.
• Fix Tornado integration to work with Tornado 6.
• Do not evaluate Django QuerySet when trying to capture local variables.
  Also an internal hook was added to overwrite repr for local vars.