doc/Makefile.doc * added dependency between xml files and .ref files
doc/Makefile.doc
* added dependency between xml files and .ref files

doc/docbook.py
* more informative diagnostic for un-numbered subsections with an id

doc/rst.py
* made literal code blocks smaller in latex output,
    for better match with docbook style
* made alerts and inline literals use smaller font size

doc/en/ch01.rst
* updated for distinction in cumulative/non-cumulative freqdist plots

doc/en/ch02.rst
* wrote section on code re-use, with subsections on text editor,
  functions and modules
* added example of ConditionalFreqDist.plot() for inaugural address
  corpus, inspired by recent post on languagelog
  http://languagelog.ldc.upenn.edu/nll/?p=696

doc/en/ch14.rst
* more notes

nltk/probability.py
* added cumulative=True flag to FreqDist.plot() and
  ConditionalFreqDist.plot()
* made these plot functions not scale their data (as percentages)
  since this makes them more like ProbDists instead of FreqDists
* added comment in code about anomalous name of ProbDist.freq()



svn/trunk@6689

nltk/nltk,nltk/nltk,nltk/nltk