PCCA contains deprecated method

[Zsailer]

In the PCCAPlus class from lumping.pcca_plus, the optimize_A method uses Scipy's optimize.anneal method. This is deprecated in SciPy v0.14.0 version, and it uses optimize.basinhopping instead. Scipy returns a couple warnings about this.

I have not yet investigated these methods enough to see how much of a difference this makes. I'd be happy to look into this more and submit a PR with the new method. I'm sure it's pretty trivial.

Thanks for all the great work here, too!