Fix for issue #607

This is a fix for #607. Below is a summary of the work done:

* mysite/base/templates/meta.html -- Done. Removed two paragraphs on the celeryd workers
* docs/getting_started/installation.rst -- Done. Removed mention of
dcelery
* mysite/custom/management/commands/customs_daily_task.py -- Removed
variable django.conf.settings.CELERY_ALWAYS_EAGER=True
* mysite/project/tasks -- Removed this file completely. It was a celery
task and removing it did not fail any tests
* mysite/_profiling.py -- Removed the settings.CELERY_ALWAYS_EAGER
variable. Should we remove the entire _profiling module instead ? It
doesn't seem to be used anywhere else.
* mysite/deployment_settings.py -- Removed the
settings.CELERY_ALWAYS_EAGER variable.
* mysite/settings.py -- 1. Removed celery and dcelery from the installed
apps, 2. Removed CELERY_ALWAYS_EAGER variables throughout the file, 3.
Removed the celery initialization that included celery import and
calling dcelery.setup_loader 4. Removed all other mentions of celery
that were in comments
* mysite/testrunner.py -- Removed the settings.CELERY_ALWAYS_EAGER from
the function override_settings_for_testing
setup.py -- Removed the 'celery==2.2.7' entry from the install_requires
list