synchronize compiler oops with their descriptions
computils; allocate N instruction blocks.
support outputting strings for debugging.
update too change in library(lineutils).
fix meta decl to agree with new name.
allow setting file ownership, and make sure preds created by aux
programs have an owner file.
qly is not a source file.
SWI functors is now dynamic
avoid int
allow application to set source file, useful in saved states.
reorganise code to avoid duplicate goal_expansion.
always deref arguments to built-ins.
move docs around.
store away all directives we find.
just say cmp preds are binary.
extend nb_setarag/3 to call a default case at initialization, ie,
  nb_getval(a, X, X=start).
and just that.
remove debugging stuff.
fix compiltion of binary tests to use a long instruction.
move gramar preprocessing here.
store loaded files state.
push directives to as early as possible.