Add requirement for Celery >= 2.5.0
fix google auth option handling
sometimes worker dict has None values. Fixes #276
Merge pull request #275 from morty/add-celery-version-requirement

Add requirement for Celery >= 2.5.0
Merge pull request #277 from kouk/authoptionsfix

fix google auth option handling
Merge pull request #278 from kouk/fix276

sometimes worker dict has None values. Fixes #276
Use app in bugreport
Improve logging message
Options can be passed via environment variables #270
Options passed via environment variables should have FLOWER_ prefix #255

GOOGLE_OAUTH2_KEY, GOOGLE_OAUTH2_SECRET and GOOGLE_OAUTH2_REDIRECT_URI
options will work for backward compatibility
Update options docs
Update tornado version requirement #272
Babel is included in requirements/default.txt
Refactor active task calculation
Fix a typo
Move options to a special module
Add abort task endpoint