Task methods now works with ALWAYS_EAGER.  Closes #1478

Conflicts:
	celery/app/task.py
Proxy: finally may mask evaluate errors
Simplify forking_enable selection

Conflicts:
	celery/worker/components.py
Task decorator should not be lazy if app already finalized.  Closes #1571
Now depends on billiard 2.7.3.34
Now depends on kombu 2.5.15
Updates Changelog
Bumps version to 3.0.24