get rid of string I/O, did not add much
getc is never actually used by Prolog
try to use system I/O, even if it may be slower, at least for now.
extend IO C-interface to allow reading clauses
file exists system predicate
$source_file -> $user source
hide and make system preds
fix check_head_and_body
user_expansion never fails
goal expansion is controlled b dynamic procedure
add must_be_of_type predicate_indicator
fix neat_call, debug flag is user controlled
use simplecudd, not ptoblogbdd
compile all of myddas
fx junk in file_name
fix warnings
use common file opening struct and funds
avoid pairs module
fix db queues
