Python parsing module

Version 2.0.2 - April, 2014
---------------------------
- Extended "expr(name)" shortcut (same as "expr.setResultsName(name)")
  to accept "expr()" as a shortcut for "expr.copy()".

- Added "locatedExpr(expr)" helper, to decorate any returned tokens
  with their location within the input string. Adds the results names
  locn_start and locn_end to the output parse results.

- Added "pprint()" method to ParseResults, to simplify troubleshooting
  and prettified output. Now instead of importing the pprint module
  and then writing "pprint.pprint(result)", you can just write
  "result.pprint()".  This method also accepts addtional positional and
  keyword arguments (such as indent, width, etc.), which get passed 
  through directly to the pprint method 
  (see http://docs.python.org/2/library/pprint.html#pprint.pprint).

- Removed deprecation warnings when using '<<' for Forward expression
  assignment. '<<=' is still preferred, but '<<' will be retained
  for cases whre '<<=' operator is not suitable (such as in defining
  lambda expressions).

- Expanded argument compatibility for classes and functions that
  take list arguments, to now accept generators as well.

- Extended list-like behavior of ParseResults, adding support for
  append and extend. NOTE: if you have existing applications using
  these names as results names, you will have to access them using
  dict-style syntax: res["append"] and res["extend"]

- ParseResults emulates the change in list vs. iterator semantics for
  methods like keys(), values(), and items(). Under Python 2.x, these
  methods will return lists, under Python 3.x, these methods will 
  return iterators.

- ParseResults now has a method haskeys() which returns True or False
  depending on whether any results names have been defined. This simplifies
  testing for the existence of results names under Python 3.x, which 
  returns keys() as an iterator, not a list.

- ParseResults now supports both list and dict semantics for pop().
  If passed no argument or an integer argument, it will use list semantics
  and pop tokens from the list of parsed tokens. If passed a non-integer
  argument (most likely a string), it will use dict semantics and 
  pop the corresponding value from any defined results names. A
  second default return value argument is supported, just as in 
  dict.pop().

- Fixed bug in markInputline, thanks for reporting this, Matt Grant!

- Cleaned up my unit test environment, now runs with Python 2.6 and 
  3.3.

Version 2.0.1 - July, 2013
--------------------------
- Removed use of "nonlocal" that prevented using this version of 
  pyparsing with Python 2.6 and 2.7. This will make it easier to 
  install for packages that depend on pyparsing, under Python 
  versions 2.6 and later. Those using older versions of Python
  will have to manually install pyparsing 1.5.7.

- Fixed implementation of <<= operator to return self; reported by
  Luc J. Bourhis, with patch fix by Mathias Mamsch - thanks, Luc
  and Mathias!

Version 2.0.0 - November, 2012
------------------------------
- Rather than release another combined Python 2.x/3.x release
  I've decided to start a new major version that is only 
  compatible with Python 3.x (and consequently Python 2.7 as
  well due to backporting of key features). This version will
  be the main development path from now on, with little follow-on
  development on the 1.5.x path.

- Operator '<<' is now deprecated, in favor of operator '<<=' for
  attaching parsing expressions to Forward() expressions. This is
  being done to address precedence of operations problems with '<<'.
  Operator '<<' will be removed in a future version of pyparsing.