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)