readme is too wordy

[mdsumner]

Drop the manifesto and complaining:

... geospatial is cool ... 3D is cool ... putting them together is a challenge ...

• Convert geospatial objects to 3D with as.mesh3d() - works for matrix, raster, sf-polygons, sp-polygons, silicate-triangles

• Plot geospatial objects with plot3d() - works for matrix, raster, sf (any type), sp, trip, silicate

• Merge raster and vector with as.mesh3d - elevate polygons or lines with a raster dem

• Drape imagery onto raster or polygon surfaces with as.mesh3d - image_texture argument

• Create any mesh above and reproject to any projection, including geocentric

• Use shade3d() or plot3d() or wire3d() from the rgl package to plot any mesh3d object created. (plot3d() also calls the converters for non-mesh types, so we can quickly get a 3D scene from any spatial data)

• For developers: delve into the technical details, all code is as modular as possible and relies on basic workhorse packages that do one simple task ...

... etc.