Patch #6386. Thanks to John Darrington for review and for the

updates to gnumeric-reader.c.

* dictionary.c (make_hinted_name): New function.
(make_numeric_name): New function.
(dict_make_unique_var_name): New function.

* gnumeric-reader.c (devise_name): Removed.
(munge_name): Removed.
(gnumeric_open_reader): Use new function
dict_make_unique_var_name.

* short-names.c (set_var_short_name_suffix): Use new function
str_format_26adic.