• Shorten the package description to the 180 characters pub.flutter-io.cn allows. No code changed.

First release.

• Reads .3mf, .glb, .obj (loose or zipped with its .mtl) and .stl, binary or ASCII.
• readModel works out the format from the file's content, never from its extension.
• Returns parts with a stable id, a name, a mesh and a colour as #RRGGBB.
• Reports what a file asked for and the reader does not do as ModelWarning codes, instead of drawing it wrong in silence.
• Levels units and colour across formats: metres become millimetres, and linear glTF colour comes back as the sRGB hex a person picked.