Remove unused get-default and find-slot.
Remove unused get-default and find-slot.

get-default can be replaced by the much simpler.

  (getf (mopu:slot-properties 'gtk-browser 'search-engines) :initform)

For user configs, the new commended way is to use define-configuration.
The slot initform can be invoked via the new %slot-default implicit variable.

jmercouris/NeXT,jmercouris/NeXT