pgsql: Create the pg_pltemplate system catalog to hold template

Log Message:
-----------
Create the pg_pltemplate system catalog to hold template information
for procedural languages.  This replaces the hard-wired table I had
originally proposed as a stopgap solution.  For the moment, the initial
contents only include languages shipped with the core distribution.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        catalogs.sgml (r2.112 -> r2.113)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/catalogs.sgml.diff?r1=2.112&r2=2.113)
    pgsql/doc/src/sgml/ref:
        create_language.sgml (r1.40 -> r1.41)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_language.sgml.diff?r1=1.40&r2=1.41)
        createlang.sgml (r1.36 -> r1.37)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/createlang.sgml.diff?r1=1.36&r2=1.37)
    pgsql/src/backend/catalog:
        Makefile (r1.56 -> r1.57)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/Makefile.diff?r1=1.56&r2=1.57)
    pgsql/src/backend/commands:
        functioncmds.c (r1.66 -> r1.67)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/functioncmds.c.diff?r1=1.66&r2=1.67)
        proclang.c (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/proclang.c.diff?r1=1.61&r2=1.62)
    pgsql/src/include/catalog:
        catversion.h (r1.300 -> r1.301)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.300&r2=1.301)
        indexing.h (r1.90 -> r1.91)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/indexing.h.diff?r1=1.90&r2=1.91)
    pgsql/src/include/commands:
        proclang.h (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/proclang.h.diff?r1=1.10&r2=1.11)
    pgsql/src/test/regress/expected:
        sanity_check.out (r1.28 -> r1.29)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/sanity_check.out.diff?r1=1.28&r2=1.29)

Added Files:
-----------
    pgsql/src/include/catalog:
        pg_pltemplate.h (r1.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_pltemplate.h?rev=1.1&content-type=text/x-cvsweb-markup)