Implements steeves dynamic tasks as task.replace. Issue #817
add a groupmeta_collection option to save group results in a different collection than results and add a 'bson' fake kombu encoder to allow pymongo to serialize natively data in mongodb
Fix typo.

There is no `self` in the context, `__name__` seems reasonable.
Merge pull request #2120 from flyingfoxlee/patch-1

Fix typo.
Fix for #2120
A few small grammar changes

Fixed a couple inconsistencies and run on sentences to improve the flow of the introduction.
Tests passing

Conflicts:
	celery/app/base.py
	celery/tests/app/test_app.py
missing an 'all' because 'call' ate it
Tests passing
Merge pull request #2128 from ubershmekel/patch-1

missing an 'all' because 'call' ate it
fix for #2076
Change default mask
pass tests
Tests passing

Conflicts:
	celery/tests/bin/test_celeryd_detach.py
Updates Changelog

Conflicts:
	Changelog
Updates Changelog
Preserve old umask parsing behavior so that --umask starting with 0 is octal, otherwise decimal
Merge branch 'rossdeane/master'
Improvements for #2134 (which fixes Issue #2076)
ghettomq is discontinued