(1) removed three-part table of config name components from Installing

(1) removed three-part table of config name components from Installing
    appendix (too hard to maintain, esp w/recent versions of config.sub).
    Also corrected xref to this section accordingly.
(2) updated sample output from config.sub to match latest variation of
    that script
(3) minor editing to gnu contrib text on set/show remotedebug