Allow to specify any custom arguments for celery workers. This will allow to insert "-Ofair" in celery 3.1 wihout making the options bloated on  sparks side.
Don't make my defaults be the defaults for everyone. Spotted by @Eliotberriot.
Missing space, very important for arguments chaining.
Empty the README and refresh the remaining parts. Contents is in the Github Wiki now. More easily editable by contributors (and me, too).
version bump
Merge branch 'release/3.12'
Merge branch 'release/3.12.1'

Conflicts:
	sparks/__init__.py
	sparks/fabric/utils.py
Merge branch 'release/3.13'
Do the same as last patch, for LocalConfiguration too. Remove obsolete module lsb_release. Thanks @eliotberriot again.
version bump
Merge branch 'release/3.13.1' into develop
Merge branch 'develop' of github.com:1flow/sparks into develop