rc: misc enhancements to improve timing in executed scripts, and to simplify scripts.

rc: misc enhancements to improve timing in executed scripts, and to simplify scripts.

These enhancements are mainly to improve timing in executed scripts - especially
scripts for logging - and to simplify scripts.
1) Wait time on suffixed script files - don't wait if the filename has a '&' in it.
2) killall_tk has better timer granularity. Tenths of second instead of whole second.
3) In exec_service, added ability to know if the service was requested by the GUI
   or by the "service" command-line command.
4) Start/stop logging doesn't restart cron & firewall if it was called from the command
   line. These are restarted so they can pick up parameters from the GUI, in case any
   changed. But none will if is was "service logging restart".
7) Better timer granularity in do_service.