Hooks

- Added an example hook script, on-exit.shadow-file, which simulates the now
  deprecated (soon to be removed) shadow file feature.
Shadow Files

- Removed the shadow file feature, which has caused much suffering since version
  1.4.3.
Hooks

- Added a master control, rc.hooks, which defaults to 'on', but can be used
  to disable hook processing in general.
CmdDiagnostics

- Represented the hooks master switch, rc.hooks, on the diagnostic output.