remove caching of case distinctions
remove warnings in PreludeNat
generate integers in MonadUnique
make Cache explicit about its keys and values
Merge branch 'master' of https://github.com/apunktbau/co4
introduce co4 monad
adjust tests to previous commit
Merge branch 'master' of https://github.com/apunktbau/co4

Conflicts:
	CO4/Test/WCB_Matrix.standalone.hs