Add a stderr and stdout to the Celery commands

The management commands are broken with Django 1.7, which complains because the Command has no std[out|err] attribute.
Fix WorkerState.is_alive() not accurate when settings.USE_TZ = True and the local timezone is not UTC
Merge branch 'release/fix_worker_state_is_alive' into feature/fix_worker_state_is_alive
let's make it a bit more Python 3 compatible
fix PeriodicTaskAdmin (__unicode__)
depend less on 3rd parties to be Py2/3 compatible
remove unnecessary __unicode__ method from PeriodicTaskAdmin
Merge pull request #337 from piotrbulinski/master

let's make it a bit more Python 3 compatible
Adds Piotr Bulinski to AUTHORS
Merge pull request #332 from rockallite/feature/fix_worker_state_is_alive

Fix WorkerState.is_alive() not accurate when settings.USE_TZ = True and ...
Merge pull request #326 from artscoop/patch-1

Add a stderr and stdout to the Celery commands
Fix WorkerState.is_alive() not accurate when settings.USE_TZ = True and the local timezone is not UTC
Adds Rockallite Wulf to AUTHORS
Add a stderr and stdout to the Celery commands

The management commands are broken with Django 1.7, which complains because the Command has no std[out|err] attribute.
Disable model validation on Django 1.7.  Closes #336
flakes
Merge branch 'master' of github.com:celery/django-celery
os.environment must be bytes.  Closes #344