lib: replace almost all fprintfs in library with _n_d_log

lib: replace almost all fprintfs in library with _n_d_log

This is not supposed to change any functionality from an end user
point of view. Note that it will eliminate some output to stderr. The
query debugging output is left as is; it doesn't really fit with the
current primitive logging model. The remaining "bad" fprintf will need
an internal API change.