pgsql: Add tools/find_gt_lt to find < and > in SGML source.

Log Message:
-----------
Add tools/find_gt_lt to find < and > in SGML source.

Lowercase some uppercase tags so tools is more reliable at finding
problems.

Modified Files:
--------------
pgsql/doc/src/sgml:
client-auth.sgml (r1.70 -> r1.71)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/client-auth.sgml.diff?r1=1.70&r2=1.71)
contacts.sgml (r1.5 -> r1.6)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/contacts.sgml.diff?r1=1.5&r2=1.6)
installation.sgml (r1.228 -> r1.229)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/installation.sgml.diff?r1=1.228&r2=1.229)
protocol.sgml (r1.57 -> r1.58)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/protocol.sgml.diff?r1=1.57&r2=1.58)
release.sgml (r1.323 -> r1.324)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml.diff?r1=1.323&r2=1.324)
rules.sgml (r1.39 -> r1.40)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/rules.sgml.diff?r1=1.39&r2=1.40)
runtime.sgml (r1.302 -> r1.303)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/runtime.sgml.diff?r1=1.302&r2=1.303)
xindex.sgml (r1.37 -> r1.38)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xindex.sgml.diff?r1=1.37&r2=1.38)
xoper.sgml (r1.32 -> r1.33)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xoper.sgml.diff?r1=1.32&r2=1.33)
pgsql/doc/src/sgml/ref:
pg_restore.sgml (r1.49 -> r1.50)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_restore.sgml.diff?r1=1.49&r2=1.50)
pgsql/src/tools:
RELEASE_CHANGES (r1.54 -> r1.55)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/RELEASE_CHANGES.diff?r1=1.54&r2=1.55)

Added Files:
-----------
pgsql/src/tools:
find_gt_lt (r1.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/find_gt_lt?rev=1.1&content-type=text/x-cvsweb-markup)