Alternative example structure.

[neochief]

How about structuring implementations in the factory method as a separate package, to show the actual value to the student? I'm looking forward t your comments.

[fadeevab]

@neochief Thank you for patch, I think it makes sense. Just let's make a bit of refactoring over the patch structure: it's a little bit overcomplicated because of "too much of decoupling" :).

1. Move the app/* files into the render-dialog root.
2. Rename lib.rs to mod.rs in the submodules.
3. Now, you can rid of Cargo.toml in the submodules.
4. Make modules visible to the project:

   mod init;
   mod gui;
   mod html_gui;
   mod windows_gui;
   
   use init::initialize;
   
   fn main() {.....}

5. Run cargo fmt

[fadeevab]

@neochief Check it out: PR #3
I believe we can simplify like that, and I applied your README, comments, and other suggestions.