adding feature:skip user's non-interested items when generate recommendation for user.

[han henry]

Hi,All

Sometimes user's dislikes some recommendation we generated ,he/she does not
want to see the recommended items again.

Here is a example from Amazon.com (see the attachment ).

I have written one patch for it.the logic as following :

1) Dump user's non-interested items to HDFS, format like userId+"_"+item_id.
before we run RecommenderJob
2) Load user's invalid data to HashMap when AggregateAndRecommendReducer
setup
3) Skip user's non-interested items when choose TOP N recommendations for
user.

Does it make sense and can merge to the repository ?