Fix deprecated code in brill tagger, found when checking doctests in ch05. Spell check ch04-ch06, doctests on ch04-ch05.  Convert further reading section of ch05 to prose; move some misc stuff to ch05-extras. Mention summer schools in ch00.
Fix deprecated code in brill tagger, found when checking doctests in ch05.
Spell check ch04-ch06, doctests on ch04-ch05.  Convert further reading
section of ch05 to prose; move some misc stuff to ch05-extras.
Mention summer schools in ch00.


svn/trunk@7900

nltk/nltk,nltk/nltk,nltk/nltk