Viz: initial dataset visualizations

[JohnTigue]

So, the Brightfield Challenge dataset is basically just a raw z-stack of 2D images (plus SWC files), each neuron's data in a separate directory. This project seeks to explore "doing neuroscience on Colab." So, crank out some code that does basic image processing on the image stack.

• Basic TIFF view with pan and zoom, workin elegantly on Colab (Viz: static image viewer w/ pan and zoom (Matplotlib version) #34)
• Animated GIF of stack: all images into a single GIF (Viz: image stack as animated GIF #20)
• Z-stack explorer: a slider for z-index to a single image (Viz: Dataset Z-stack explorer, single image #22)
• HTML5 movie: Folks can play the movie, or manipulate time to move up/down stack (Stack as web video #199)
• Maximal Image Projection (MIP, Minimal technically, MinIP): 3D z-stack to 2D (Viz: Minimum Image Projection #28)
• MinIP colorized 4-up (Viz: MinIP colorized four-up #45)
• Depth coded colorized MinIP (Viz: depth coded MinIP #32)