Nelder mead

CODE REVIEW

Just wanted to get this up but further improvements are coming.  This implements a Nelder Mead convergence algorithm as long as you are converging to a point.  I was hoping this would work with math.Inf as well (thereby finding min and max) but the diffs get lost in the subtraction involving math.MaxFloat64.  I'll have to implement a separate code path for min and max.

Nelder Mead implemented as seen here: http://www.webpages.uidaho.edu/~fuchang/res/anms.pdf

Going to use that same paper to make the scalars adaptive.  When that's done, I'm going to implement constraints as seen here: http://www.emse.fr/~leriche/GBNM_SMO_1026_final.pdf

Finally, can use the algorithm seen there and here: http://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/MonK/MoKA1-04ge_ghiasimh224461p.pdf

to attempt and ensure any result is global (which Excel doesn't do I don't believe).

@tannermiller-wf @beaulyddon-wf @alexandercampbell-wf @stevenosborne-wf @tylertreat-wf @ericolson-wf @rosshendrickson-wf 
I wish I had time to read those papers, but given that I haven't, are these values specifically called out in the papers? Or are they chosen by you and going to be further tweaked? If they're going to be tweaked, then it might make sense to expose them to a user of the package so that it can be tweaked at runtime.