halcmd - add commands echo and unecho and -e

Echo will print the commands sent to HAL to standard error.
This allows one to read the commands sent via a script that
sends it's stdout to dev/Null (while debugging). Stepconf and Pncconf
are examples.
-e set the session to echo from the beginning. It can be overridden
with the unecho command at any time.
halrun -add -e option and allow -s and -e with interactive.

While you still can't have halrun -sk with no filename (legal in 2.5),
-Is or -s gets you the same. -Ise is legal (adds command echo)
-s still get you no prompt (different from 2.5)

Thanks Dewey for the suggestion.