Lots of changes. Expanded naming scheme to have more standard '_' names.
Changed the stimulus design, such that each adapting block, even those
of the same frequency band and contrast (ie, different repetitions), has
a different random noise base. This means that each adapter is really a
draw from the environment, rather than all of them being the same draw.
Now using MATLAB's `filfilt` to do zero-phase filtering, rather than
the `filter` function, which introduces a phase lag. Adding contrast
into pre-computation of filtered adapting stimuli, rather than doing it
on each frame. Also streamlined saving of all data, and verified that
stimulus is faithfully recapitulated by all `stimdb` code.