Don't set minZoom in the SamplingParams in the Tutorials

[mousebird]

In general we shouldn't be setting minZoom in the MaplySamplingParams. We can set it in the tileInfo instead. The SamplingParams describe how the world is broken down and typically need to start at level 0. Sometimes level 1 if we're doing something weird (usually in weather).

So we need to remove that line from all the tutorials. I've already done it from the test case.

[TimSylvester]

I merged site-source-update, but wasn't able to confidently verify it due to differences in the HTML generation. Please check it over. The local_image_layer page looks right, but I'm still seeing MaplyRemoteTileSource all over.