Add representative DV values for DV bins for calculation of a continuous expected DV

[gdcutting]

"Directed, Fit: Add representative DV values for DV bins for the calculation of a continuous expected DV.
Explanation & Algorithm: If the DV was originally quantitative and was binned, then an expected calculated continuous DV value can be calculated as <DV|IV> = sum over DV states_i{ q(DV_i|IV) * DVrep_i }, where DVrep_i is the representative DV value for the i-th DV bin. User should be able to specify these representative values by a string of values on the web input page for Fit instead of the "calculate expected DV" line. Have the new line that replaces it read "Representative values for DV bins (optional)" followed by a box in which the user can write values -- e.g., for a DV with cardinality three, the user might input something like "1.4,2.7,3.9". (Reading this in should tolerate white spaces on either side of the commas.) Do this expected value calculation in Fit if and only if the user has specified these representative DV values. It should also be possible to specify these representative values in the Occam input file with the following syntax (the first line indicates that parameters follow in the second line):"