Keep the gradient flowing

Preparing a new release

Last days I've been busy preparing the first public beta of SymPy 0.6.5. Most of the time was spent solving a bug that made documentation tests fail under python2.4, but now that this is solved, I hope that by the end of the week we could have a final release. When this release is published, we'll merge my query module and work on getting it right for 0.7.