Small Changes to Server API

@caleighroleck Most of the changes that we discussed should be here. Here is what I noted and attempted to change:

[x] Remove Dirichlet priors calculation altogether
[x] Remove code that raises to prior parameter
[x] Remove ** (parameter - 1) from frequency[species][codon] calculation
[x] Remove code and comments that raises 10 to the power of RCA
[x] Change value of et to 0.05 in absolute difference calculation
[x] Change server API to permit user setting number of itereations (will need to update UI to support this)

Regarding this note on google docs:

I also wonder if we include the final absolute value and sum of squares scores and the predicted expression values on the website - all are returned with the optimize_multitable functions

I think I am actually returning this to the website, I just am not displaying the data. So I can change that as well.

If you want to look at the code changes specifically in oengine.py, let me know if things look ok.

nleroy917 / optipyzer

Small Changes to Server API #39