pull request #744 - specifying items in lua files

Pull request #744 from vultur-cadens:  the object specification
supported by des.object() was ambiguous for items whose name in
objects[] doesn't include the object class name.  For instance ring
and spellbook of protection are just named "protection" (unlike
"cloak of protection" which has its full name).

Fixes #744

The commit message for pull request #743 misidentified it as #744,
so didn't get marked closed properly.  Do that now...

Closes #743