Fix optimize defaults for older scipy versions for L-BFGS-B

Enabling Optimizer class to work with < 0.12 versions of Scipy for L-BFGS-B can be tricky. The parameters of L-BFGS-B function changed from 0.11 to 0.12.  Here is a workaround. I also added some more prints reporting what is actually happening when < 0.12. GGT! @arokem release the Kraken!
why is eps changed to the lowest possible value? you might get convergence issues at line 155 for example, and anywhere else it's used.