Relaxin the PVP with regards to adding instances

[Henning Thielemann]

On Tue, 11 Sep 2012, Michael Sloan wrote:

> Yup, I can agree to that!  A naming + namespace convention for this
> variety of package might be good, for discoverability.

We might agree on a Cabal Category like OrphanInstance that every such 
package should be in. Since a package can be in multiple categories you 
can put it both in the OrphanInstance category and in the categories of 
the packages where you take the class and the type from.