--app argument: Make sure found attribute is not a module.  Closes #1647
Temporary until 3.1.4 (Issue #1647)
[requirements] pkgutils now depends on setuptools 1.3.2 or later
[requirements] Adds wheel to pkgutil deps
[requirements] Adds wheel to pkgutil deps
Merge branch 'master' of github.com:celery/celery
ALWAYS_EAGER is an antipattern for unittests, removes the old tutorial (See #1648)
Use -A proj to start database scheduler
Merge branch 'master' into 3.1