sympy/sympy — pull request #1095 by rlamy (2012-02-29 21:06:31+00:00)
Title: Refactor ExprCondPair

A few small changes to simplify Piecewise by trying to get rid of ExprCondPair incrementally. The 2nd commit also implements args canonicalisation as discussed in [issue 3025](http://code.google.com/p/sympy/issues/detail?id=3025).

This has to go in before #1009, but shouldn't interfere too badly with it, since #1009 removes ExprCondPair in one go in its first commit.