Potentail bug while calculating approxmiate median

[utkrist]

Line 65 of this file edmTail.cpp contains the following line
return lWeight*(quant*(lu-l)+l) + rWeight*(quant*(u-rl)+rl);
where

lu = (u+l)/2;
rl = (u+lu)/2;

This seems wrong. Shouldn't this be:
return lWeight*(quant*(lu-l)+l) + rWeight * (quant*(u-lu)+lu);

Simple visulization of the problem:
say we have the line return lWeight * ML + rWeight * MR;
The current implementation is returning the first case while it should be the second case.

l.....................ML..................... lu ......................rl.............MR.............u

l.....................ML.................... lu ......................MR..........................u