Nltk-ma

* Code:
- corpus readers for Senseval 2 and TIMIT
- clusterer (ported from old NLTK)
- support for cascaded chunkers
- bugfix suggested by Brent Payne
- new SortedDict class for regression testing
* Contrib:
- CombinedTagger tagger and marshalling taggers, contributed by Tiago Tresoldi
* Corpora:
- new: Senseval 2, TIMIT sample
* Tutorials:
- major revisions to programming, words, tagging, chunking, and parsing tutorials
- many new exercises
- formatting improvements, including colorized program examples
- fixed problem with testing on training data, reported by Jason Baldridge

* switch to new style classes
* repair FSA model sufficiently for Kimmo module to work
* port of MIT Kimmo morphological analyzer; still needs lots of code clean-up and inline docs
* expanded support for shoebox format, developed with Stuart Robinson
* fixed bug in indexing CFG productions, for empty right-hand-sides
* efficiency improvements, suggested by Martin Ranang
* replaced classeq with isinstance, for efficiency improvement, as suggested by Martin Ranang
* bugfixes in chunk eval
* simplified call to draw_trees
* names, stopwords corpora

* Peter Spiller's concordancer
* Will Hardy's implementation of Penton's paradigm visualization system
* corpus readers for presidential speeches
* removed NLTK dependency
* generalized CFG terminals to permit full range of characters
* used fully qualified names in demo code, for portability
* bugfixes from Yoav Goldberg, Eduardo Pereira Habkost
* fixed obscure quoting bug in tree displays and conversions
* simplified demo code, fixed import bug