Update release notes for changes through 2009-05-11.  Also some minor copy-editing and reordering of items.
Update release notes for changes through 2009-05-11.  Also some minor
copy-editing and reordering of items.

kmjungersen/PostgresXL,yazun/postgres-xl,Postgres-XL/Postgres-XL,yazun/postgres-xl,ashwinstar/gpdb,tpostgres-projects/tPostgres,kmjungersen/PostgresXL,Postgres-XL/Postgres-XL,Postgres-XL/Postgres-XL,edespino/gpdb,arcivanov/postgres-xl,greenplum-db/gpdb,ovr/postgres-xl,zeroae/postgres-xl,adam8157/gpdb,zeroae/postgres-xl,edespino/gpdb,arcivanov/postgres-xl,edespino/gpdb,oberstet/postgres-xl,lisakowen/gpdb,oberstet/postgres-xl,xinzweb/gpdb,tpostgres-projects/tPostgres,ovr/postgres-xl,adam8157/gpdb,yuanzhao/gpdb,adam8157/gpdb,ovr/postgres-xl,jmcatamney/gpdb,Chibin/gpdb,kmjungersen/PostgresXL,jmcatamney/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,postmind-net/postgres-xl,pavanvd/postgres-xl,snaga/postgres-xl,snaga/postgres-xl,greenplum-db/gpdb,Chibin/gpdb,edespino/gpdb,Chibin/gpdb,snaga/postgres-xl,50wu/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,oberstet/postgres-xl,yazun/postgres-xl,zeroae/postgres-xl,postmind-net/postgres-xl,Chibin/gpdb,edespino/gpdb,yuanzhao/gpdb,lisakowen/gpdb,lisakowen/gpdb,edespino/gpdb,50wu/gpdb,lisakowen/gpdb,jmcatamney/gpdb,kmjungersen/PostgresXL,yazun/postgres-xl,50wu/gpdb,tpostgres-projects/tPostgres,yuanzhao/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,adam8157/gpdb,Chibin/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,techdragon/Postgres-XL,yuanzhao/gpdb,adam8157/gpdb,arcivanov/postgres-xl,edespino/gpdb,Chibin/gpdb,edespino/gpdb,arcivanov/postgres-xl,jmcatamney/gpdb,Chibin/gpdb,kmjungersen/PostgresXL,adam8157/gpdb,pavanvd/postgres-xl,Postgres-XL/Postgres-XL,jmcatamney/gpdb,pavanvd/postgres-xl,greenplum-db/gpdb,50wu/gpdb,postmind-net/postgres-xl,yuanzhao/gpdb,yuanzhao/gpdb,postmind-net/postgres-xl,greenplum-db/gpdb,snaga/postgres-xl,zeroae/postgres-xl,xinzweb/gpdb,yuanzhao/gpdb,50wu/gpdb,tpostgres-projects/tPostgres,lisakowen/gpdb,xinzweb/gpdb,edespino/gpdb,adam8157/gpdb,yazun/postgres-xl,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,50wu/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,Postgres-XL/Postgres-XL,arcivanov/postgres-xl,postmind-net/postgres-xl,techdragon/Postgres-XL,lisakowen/gpdb,oberstet/postgres-xl,pavanvd/postgres-xl,techdragon/Postgres-XL,ovr/postgres-xl,greenplum-db/gpdb,xinzweb/gpdb,Chibin/gpdb,xinzweb/gpdb,xinzweb/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,ashwinstar/gpdb,lisakowen/gpdb,yuanzhao/gpdb,techdragon/Postgres-XL,edespino/gpdb,arcivanov/postgres-xl,techdragon/Postgres-XL,snaga/postgres-xl,adam8157/gpdb,ovr/postgres-xl,Chibin/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,50wu/gpdb,Chibin/gpdb,tpostgres-projects/tPostgres,ashwinstar/gpdb