add support for ID up to int64 

git-svn-id: http://svn.osgeo.org/postgis/trunk@11889 b70326c6-7e19-0410-871a-916f4a2858ee
change to int8 for twkb ID in doc

git-svn-id: http://svn.osgeo.org/postgis/trunk@11890 b70326c6-7e19-0410-871a-916f4a2858ee