sympy/sympy — pull request #954 by smichr (2012-01-10 18:11:13+00:00)
Title: fix -float in dpll2 for py 2.5

In py 2.5 -float(0) gives -0.0 whereas in higher versions it gives 0.0. This fixes the failing doctests in 2.5 under windows 32-bit.