#2478: incorporated Kahif Rasul's trunk fixes and also logic to enable tiger geocoder in 2.1 extension

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@11969 b70326c6-7e19-0410-871a-916f4a2858ee
#2466 point json-c to github loc instead of old 0.9 loc

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@11971 b70326c6-7e19-0410-871a-916f4a2858ee