Proposal: Tidy up and export PSQ from base

[Edward Z. Yang]

Excerpts from Felipe Almeida Lessa's message of Fri Apr 29 21:18:09 -0400 2011:
> Why base, and not containers?

This is because the event manager still needs it to use it, and presently
base does not have containers as a dependency (I don't think that would work
anyway.)  Perhaps one alternative possibility is to put the event manager in
its own package, but I think it too provides the dependencies for a lot of
modules we traditionally associate with base.

Edward