Tweaked README.
Added a few test cases to illustrate the behavior of the PFor compressor.
Added ClueWeb09 classes, refactoring class names to reduce confusion.
Tweaked test cases.
Renamed clueweb12 classes to reduce confusion with clueweb09 classes.
New API InputFormat for Clueweb09 collection; Record counting demos.
Merge branch 'clueweb09' into working
Implemented PorterAnalyzer with stopwords list from Terrier.
updated for with working branch of lintool/clueweb