add filters support to hb.scan

[kul]

It would be a major improvement to add filters to rhbase scan functions. A prefix filter to start with would be great.

Thanks

[RevolutionAnalytics]

There is a function called hb.scan.ex that accepts filters. Please look at the bottom of the rhbase wiki page for details

https://github.com/RevolutionAnalytics/RHadoop/wiki/rhbase