pgsql: Add a variant of the Levenshtein string-distance function that

Log Message:
-----------
Add a variant of the Levenshtein string-distance function that lets the user
specify the cost values to use, instead of always using 1's.
Volkan Yazici

In passing, remove fuzzystrmatch.h, which contained a bunch of stuff that had
no business being in a .h file; fold it into its only user, fuzzystrmatch.c.

Modified Files:
--------------
    pgsql/contrib/fuzzystrmatch:
        fuzzystrmatch.c (r1.26 -> r1.27)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/fuzzystrmatch/fuzzystrmatch.c?r1=1.26&r2=1.27)
        fuzzystrmatch.sql.in (r1.9 -> r1.10)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/fuzzystrmatch/fuzzystrmatch.sql.in?r1=1.9&r2=1.10)
        uninstall_fuzzystrmatch.sql (r1.3 -> r1.4)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/fuzzystrmatch/uninstall_fuzzystrmatch.sql?r1=1.3&r2=1.4)
    pgsql/doc/src/sgml:
        fuzzystrmatch.sgml (r1.3 -> r1.4)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/fuzzystrmatch.sgml?r1=1.3&r2=1.4)

Removed Files:
-------------
    pgsql/contrib/fuzzystrmatch:
        fuzzystrmatch.h
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/fuzzystrmatch/fuzzystrmatch.h)