Fluent API for components

[astrowalker]

"Fluent" as C#/code, not CSS/Bootstrap.

Please provide fluent API -- this would allow easy way to add styling for example. If you take a look at for example FluentColumn this is basically closed class. But with Add/With method one could add extra styling in easy way (or maybe I don't know how to add them easy way ;-) ).

    public FluentColumn Add(string classes) => new FluentColumn(classes+" ",this.ToString());

Such method is not mutable, all other (already existing methods) could be rewritten avoiding mutability problem, and there would be easy way to express extra styling, like:

            var cls = col.xs.auto.Add("align-self-end");