Histograms added

To be true I started doing it yesterday and stopped around 1 am. After a few hours of minor tweaking today...



ImageViewer has a nice linear histogram option available, I also removed most of the flicker when images were redrawn using the CMemDC wrapper class.

Let me know if you feel there's a need for a logarithmic histogram.

ps. The image used is copyright Tomasz Jakobiec :)

pps. I also added a gray scale conversion filter today - looks like sepia and others may be on their way - along with some simple undo mechanism ;)