pgsql-server: XLOG file archiving and point-in-time recovery.

Log Message:
-----------
XLOG file archiving and point-in-time recovery. There are still some
loose ends and a glaring lack of documentation, but it basically works.

Simon Riggs with some editorialization by Tom Lane.

Modified Files:
--------------
pgsql-server/src/backend/access/nbtree:
nbtsort.c (r1.83 -> r1.84)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/access/nbtree/nbtsort.c.diff?r1=1.83&r2=1.84)
pgsql-server/src/backend/access/transam:
xlog.c (r1.147 -> r1.148)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/access/transam/xlog.c.diff?r1=1.147&r2=1.148)
pgsql-server/src/backend/commands:
tablecmds.c (r1.120 -> r1.121)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/commands/tablecmds.c.diff?r1=1.120&r2=1.121)
pgsql-server/src/backend/postmaster:
Makefile (r1.15 -> r1.16)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/postmaster/Makefile.diff?r1=1.15&r2=1.16)
postmaster.c (r1.411 -> r1.412)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/postmaster/postmaster.c.diff?r1=1.411&r2=1.412)
pgsql-server/src/backend/utils/misc:
guc.c (r1.219 -> r1.220)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/misc/guc.c.diff?r1=1.219&r2=1.220)
postgresql.conf.sample (r1.115 -> r1.116)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.115&r2=1.116)
pgsql-server/src/bin/initdb:
initdb.c (r1.43 -> r1.44)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/bin/initdb/initdb.c.diff?r1=1.43&r2=1.44)
pgsql-server/src/include/access:
xlog.h (r1.52 -> r1.53)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/access/xlog.h.diff?r1=1.52&r2=1.53)
pgsql-server/src/include/storage:
pmsignal.h (r1.8 -> r1.9)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/storage/pmsignal.h.diff?r1=1.8&r2=1.9)

Added Files:
-----------
pgsql-server/src/backend/access/transam:
recovery.conf.sample (r1.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/access/transam/recovery.conf.sample?rev=1.1&content-type=text/x-cvsweb-markup)
pgsql-server/src/backend/postmaster:
pgarch.c (r1.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/postmaster/pgarch.c?rev=1.1&content-type=text/x-cvsweb-markup)
pgsql-server/src/include/postmaster:
pgarch.h (r1.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/postmaster/pgarch.h?rev=1.1&content-type=text/x-cvsweb-markup)