Pass `crs` parameter into `viz`

[kylebarron]

Useful for non-geodataframe objects that don't have an associated CRS, including shapely objects and geojson-like objects.

[kylebarron]

This is a bit complex because you might want to assign a different CRS for each data object you're passing in.

For now we'll punt on this and come back to it, and suggest users to use an object like GeoDataFrame that maintains the CRS