Merge pull request #1 from IBMStreams/master

Merge in changes from the main stream
Added overview to info.xml
Added descriptions in HDFSDirectoryScan
Fixed some formatting issues
Moved documentation into SPLDOC comments
Added SPL file.
Formatted operator descriptions
Additional formatting
Formatted ordered list
More formatting
Removed extra asterisk
Merge pull request #10 from lcawley/master

Addition of descriptions in info.xml and HDFSDirectoryScan