OOZIE-9: Support (Amazon) s3/s3n schemes

Currently Oozie supports only the 'hdfs' scheme. For people having their hadoop cluster in Amazon EC2 and using S3 for storage, it would be very useful if oozie supports the 's3n/s3' scheme(s). The use case I am talking about is as follows

Hadoop cluster in Amazon EC2
Uses hdfs for intermediate storage
Uses s3 for getting input for, storing output of map-reduce jobs.

More details on the above use-case and the exceptions/failures I have seen is documented here (http://tech.groups.yahoo.com/group/Oozie-users/message/1138).

There can be other use cases as well - say use s3 as the DFS instead of HDFS.