Integrate new IP type from Tom Ivar Helbekkmo.

contrib/README

contrib/ip_and_mac/Makefile

contrib/ip_and_mac/README

contrib/ip_and_mac/ip.c

contrib/ip_and_mac/ip.sql

contrib/ip_and_mac/ip_orig.c

contrib/ip_and_mac/ipaddr.html

contrib/ip_and_mac/ipi.sql

contrib/ip_and_mac/mac.h

contrib/ip_and_mac/mac.sql

contrib/ip_and_mac/t1.sql

contrib/ip_and_mac/test.DATA

contrib/ip_and_mac/test.sql

contrib/ip_and_mac/test1.sql

contrib/ip_and_mac/test2.sql

doc/README.ipaddr

src/backend/parser/gram.c

src/backend/utils/adt/Makefile

src/backend/utils/adt/inet_net_ntop.c

src/backend/utils/adt/inet_net_pton.c