Python 2.5 slower with pyparsing 1.4.3

[Paul McGuire]

Running my Verilog parser tests, I get a 5-10% slowdown with Python 2.5 vs.
Python 2.4.1 (See http://pyparsing.wikispaces.com/News.)

I apologize for not running performance tests sooner, I only ran regression
tests on the release candidates, and those were all okay.

I'll look through the "What's New in 2.5" and see if there are some features
I can take advantage of for the upcoming 1.4.4 release (while retaining
backward compat with Py2.3).

-- Paul