Support dynamic filenames.  Fixes IBMStreams/streamsx.hdfs #4.
Fix bug that would show up with dynamicFilename not used.
Fix a problem in the runtime checking.
Add new main to clean
Adjust DynamicFilename sample to work with fileAttributeName.
Change from dynamicFileName boolean to fileAttributeName.
Merged with newest version from IBMStreams
Merge branch 'filename' of https://github.com/hildrum/streamsx.hdfs into hildrum-filename
Added build config for sample, fixed copyright
fixed comment
Merge branch 'hildrum-filename'