Merge branch 'topic/hist2'
* topic/hist2:
Add `history <NO>' support for editline(3), too
HAVE_HISTORY *is* only set when there *is* a CL
Add ARG_H, readd tty_addhist() calls, now conditionalized
Add (temporary?) global list_saw_numbers
Implement temporary solution for ARG_V
Drop enum lned_mode (we only need one bit (of it))
Add <NO> mode for `history' command..
command(), evaluate(): s-it-mode, tweaks, obsolete *autoinc*
Obsolete execute() in favour of evaluate()..
readline_input(): allow default line content