tuned;
tuned signature;
clarified check of internal names;
clarified treatment of consts -- prefer value-oriented reports;
tuned signature -- more uniform check_type_name/read_type_name;
proper reports for read_type_name (lost in 710bc66f432c);
more careful simplification of sets (cf. abf91ebd0820)---yields smaller terms
more rigid type_name demands, based on educated guesses about the tools involved here;
tuned;
renamed 'map_sum' to 'sum_map'
renamed 'map_pair' to 'map_prod'
renamed 'fset_rel' to 'rel_fset'
renamed 'cset_rel' to 'rel_cset'
more uniform check_const/read_const;
move special BNFs used for composition only to BNF_Comp;
use local copy of identity function that gets unfolded later for ID
rationalized imports
tuned
eliminated odd type constraint for read_const (see also 79c1d2bbe5a9);
renamed 'set_rel' to 'rel_set'
fixed NEWS
renamed 'vset_rel' to 'rel_vset'