more code lemmas by Rene Thiemann
removed nonstandard models from Nitpick
tuned code
tuned ML names
support 'datatype_new'-defined datatypes in Nitpick + better support for 'codatatype's
updated docs
fixed handling of 'case_prod' and other 'case' functions for interpreted types
simplified N2M code now that 'fold' is no longer used by the sugar layer + use right context in all 'force_typ' calls
added contributor
minor doc fix
removed debugging leftover
merge
N2M does not use the low-level 'fold'; removed the latter from the fp_result interface;
propagate the exception that is expected later on
renamed a pair of low-level theorems to have c/dtor in their names (like the others)
updated docs
register relator equations as spec rules only for datatypes -- for codatatypes they underspecify the function and are therefore dangerous (e.g. to Nitpick)
more caching in composition pipeline
tuning
simplify sets in BNF composition