Fixed some further QIndex related issues and replaced some tables
(eg zbin and rounding)

Also Added function (currently disabled by default) to populate the
main AC and DC quantizer tables. Using the original AC range the
resulting computed DC values give behavior broadly comparable
on the DERF set. That is not to say that the equations will hold good
over a more extended range. The purpose of this code is to make it
easier to experiment with further alterations to the Q range and distribution
of Q values plus the relative weights given to AC and DC.

The function find_fp_qindex() ensures that changes to the Q tables
are reflected in the value passed in to the first pass code.

Slight experimental adjustment to static segment Q offset.

Change-Id: I36186267d55dfc2a3d565d0cff7218ef300d1cd5