Dispersion method does not work with scipy 0.14+

[vbonvin]

The dispersion technique uses scipy.optimize.anneal, which has been deprecated since scipy 0.14
Scipy recommands to use scipy.optimize.bassinhopin instead, which does not work completely the same way.

[mtewes]

I have replaced anneal with bassinhopin to fix the demo, and on the trial curves it "seems" to work just fine. The settings for bassinhopin have to be double checked when running on many copies.

[vbonvin]

Thanks ! I'll run some tests on real light curves

[mtewes]

OK, leaving this issue open to remind us that some default settings about bassinhopin might need to be adjusted a bit, especially about CPU time (it could be that we currently make way to many iterations)...