Equations added

This partially addresses issue #321 by adding these equations: ace, enspie, heip_e, fisher_alpha, kempton_taylor_q, mcintosh_e, menhinick, shannon, simpson, and strong. In addition, variable definitions were added to berger_parker_d and to brillouin_d. 
I think these are ln ( (N+1)! ) and ln ( (n_i +1)! ) in the code. Not sure if that's good.