Added code to expose the persistence_diagram class, the bottleneck_distance function and the point class to python. Most of the commonly used methods for each class have been exported. The constructor for point now requires that a data argument be provided along with x and y coord. This needs to be made optional. The constructor for persistence_diagram could possibly be rewritten as well.

From: Dmitriy Morozov <morozov@cs.duke.edu>
Date: Fri, 22 Feb 2008 18:39:31 -0500
State: new
Subject: Incorrect sign_at() in UPolynomial<double>
Message-Id: <cd79223a108d3900-0-artemis@metatron>
category: kinetic

UPolynomial<double>::sign_at() reports -1 as the sign of -2*x + 4 at x = 2. 
Should be 0.