Merge pull request #5 from paliwalashish/master

Added Javadoc and fixed formatting issues
Client imports cleanup
Enable sample command to support multiple grouping fields
Update example workflow to show how to use the sample command to analyze extremal values in the assignment
Add handler for ISEs to the Main.java class
Typo fix
A bit of renaming/additional hcatalog work
Sketch out HCatalogSource
Fix min/max initialization in summarization code
I can't quite believe it, but this is has support for reading data from Hive via HCatalog.