async is a reserved keyword

[tutuca]

The namespace async is no longer valid as it's now a reserved keyword in python 3.6+.

Installer needs to reserve a new namespace.

[KayEss]

That is a very good point.... And not a small change either, but I don't think we have any real choice to alter it. Maybe go to asyncexec -- a bit ugly, but I guess nobody else will want it.

[tutuca]

django_async is a fine namespace IMHO :). True that is no small change.