pgestraier - pgestraier: added NULL handling for optional arguments

Log Message:
-----------
added NULL handling for optional arguments

Modified Files:
--------------
pgestraier:
test.sql (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgestraier/pgestraier/test.sql.diff?r1=1.4&r2=1.5)
pgest.sql (r1.3 -> r1.4)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgestraier/pgestraier/pgest.sql.diff?r1=1.3&r2=1.4)
pgest.c (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgestraier/pgestraier/pgest.c.diff?r1=1.7&r2=1.8)
pgestraier/t:
pgest.t (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pgestraier/pgestraier/t/pgest.t.diff?r1=1.2&r2=1.3)