Histograms added to Fancy Imshow and ColorMixer

[Chris Colbert]

Hey All,

I've added preliminary Histogramming to the fancy imshow QT widget. In
the process I added a fast Naive histogrammer to the ColorMixer for
use in this widget.

Unfortunately, I'm now suffering from circular references during
window instantiation. I'm gonna need to refactor the code a bit
because QT likes to fire off event before with main window has
finished intializing.
Everything still works, it just throws a few exceptions while the
window is intializing.

At any rate,  you can, you can check out the code from my IO branch on git.

And here is a screenshot to wet your appetite:

http://therealstevencolbert.com/dump/histograms.png

Cheers!

Chris