Added Mandelbrot Fractal

Still need to improve infrastructure.  TODO: add methods for zooming.
Also need to optimize the repaint function such that the fractal widget
draws to an image and only redraws fractal when needed.
Added Zoom - Attempted optimization

Got a zoom feature working.  Need to add a selection box, but need to
add some way to save fractal to pixmap or image which would be part of a
zoom anyway.