settings override the application, with <MYAPP>_DEBUG having the highest
priority.
+This sets the log level to 'debug' and enables full debug output on the
+error screen. If you only want the latter, see L<< $c->debug >>.
+
=head2 -Engine
Forces Catalyst to use a specific engine. Omit the
=back
+The first three also set the log level to 'debug'.
+
Calling C<< $c->debug(1) >> has no effect.
=cut