db_tool: issue #176: call view object for output

- Replaced calls to `$log->level()` with calls to `$view->update()`
GenericCLI: close #201; add aliases for update() args

- Updated POD for the `update()` method, added new argument aliases
  and whether those arguments are optional or required
GenericCLI: close #203; remove calls to Log4perl
db_tool: change overwrite message from info to warn level