improve readability of the honcho console logs in the dev environment

* colorize uwsgi and celery logs; DEBUG lines are green, WARN lines
  are yellow, ERROR lines (and tracebacks) are red
* pretty-print fact callback receiver JSON
* simplify the uwsgi log format so it's more legible

requirements/requirements_dev.txt

@@ -10,5 +10,6 @@ pytest-cov
 pytest-django
 pytest-pythonpath
 pytest-mock
+logutils
 flower
 uwsgitop