#2846 parse_address is not null safe - make immutable strict

git-svn-id: http://svn.osgeo.org/postgis/trunk@12803 b70326c6-7e19-0410-871a-916f4a2858ee
document parse_address function, add examples for parse_address and address_standardizer, fix proto for address_standardizer

git-svn-id: http://svn.osgeo.org/postgis/trunk@12805 b70326c6-7e19-0410-871a-916f4a2858ee