plproxy - plproxy: More flexible CONNECT function.

Log Message:
-----------
More flexible CONNECT function.

It allows CONNECT to take function arguments or do function calls:

CONNECT func(..);
CONNECT argname;
CONNECT $argnum;

NB: giving untrusted users ability to specify full connect string creates
security hole. Eg it can real cleartext passwords from .pgpass/pg_service.
If such function cannot be avoided, it's access rights need to be restricted.

Patch by Ian Sollars

Modified Files:
--------------
plproxy/src:
cluster.c (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/src/cluster.c?r1=1.7&r2=1.8)
function.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/src/function.c?r1=1.6&r2=1.7)
parser.y (r1.14 -> r1.15)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/src/parser.y?r1=1.14&r2=1.15)
plproxy.h (r1.15 -> r1.16)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/src/plproxy.h?r1=1.15&r2=1.16)
plproxy/sql:
plproxy_test.sql (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/sql/plproxy_test.sql?r1=1.7&r2=1.8)
plproxy/expected:
plproxy_test.out (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/plproxy/plproxy/expected/plproxy_test.out?r1=1.7&r2=1.8)