Zoom map

[sapi]

Allow zooming of the map.;

Couple of ways to do this:

• preset zooms
• click and drag

Could also offer a popup window with a pnlImagePlot bound to the same buffer.
However, this may not be possible, as from memory you can only have a view on an array when you're looking at a contiguous block (which would only be possible, for a row-major array, if the view was the entire width of the map).

Immediate todo:

• check if img[20:40,20:40,:] actually gives back a view that can be used as the input to a pnlImagePlot