Change representation of known data

Represent known data by using constant primitives of satchmo-core
instead of an explicit constructor (KConstructor) in EncodedAdt.
Remove Undefined from input language

We don't want to deal with partial functions. If the user needs partial
functions he needs to define a Maybe/Optional type.
Refine encoding
Add new encoding of unknown data
Fix toyama
Add output of cache statistics
Add output of cache statistics
Remove scheme inference in CO4.Algorithms.Eitherize
Add handling of unordered pattern matches
Add check for overlapping default matches in TH frontend

... as those would disrupt encoding of case expressions
Remove String frontend
Add 'not' to prelude
Merge branch 'master' of ssh://kernkraft/home/abau/co4

Conflicts:
	CO4/Cache.hs