getRDSOperationComplete now returns void, or exception

alterDatabase
listDatabaseProducts
isSubscribed
getConfiguration
listDatabases
getUsableBackup
createFromBackup - BROKEN - cannot create new db from old db's backup
directly
createFromLatest - cleanup DB on fail.

no more println's....
Merge pull request #211 from unwin/develop-ROGER-RDS-TEST

getRDSOperationComplete now returns void, or exception