Paint, layout, and filter properties not preserved with `set_style()`

[walkerke]

Ah, the whack-a-mole we play in software development.

In solving #39 with #99, I came across another issue. Layer states introduced by set_filter(), set_paint_property(), and set_layout_property() are not preserved when set_style() is called in a Shiny app.

No wonder the issue remains unsolved in the parent libraries...

I'll put some thought into this.