Enhanced to allow dynamic config. changes.

A bit of restructuring to allow/implement re-parsing, if there's been a
change, the configuration files each time through the main loop (just
before check_processes is run) so that changes in the monitor's behavior
can be effected dynamically, without needing to kill/restart the
process.

A couple small cleanup-changes/improvements.
Cleanup after dynamic-config restructuring

Cleaned up old cruft from previous change - removed obsolete code
replaced by the new logic, etc.
Big fix: Skip non-existent config file.

If a config file doesn't exist any more (was removed), don't try to read it.