- clean up update/feature rule handling in allowuninstall case. Automatically add...

- clean up update/feature rule handling in allowuninstall case. Automatically add the CLEANDEPS flags in solutions.

We no longer make the update/featurerule weak, but use a "autouninstall" function
instead that checks if we can solve the problem by removing a package. We also
automatically add CLEANDEPS in that case if all job rules in the problem have
CLEANDEPS set.