property for conflicts

[yrashk]

to avoid situations like mochijson2 + mochiweb

[yrashk]

(00:31) < etrepum> yeah but that's shitty because people will have both
(00:31) < etrepum> e.g. I depend on a library that only uses mochijson2 so it's a transitive dependency, but I also use mochiweb

[yrashk]

conflict property might also have an option for describing supersets.

like {conflicts, ["somelib", {overrides, "another"}]}