Smarter preserve/remove [fr]

[PRR24]

It would be great if:

• there was an option to preserve all non-inlineable CSS, which in addition to existing preserveMediaQueries would also preserve selectors like a:hover etc.
• removeHtmlSelectors would cooperate with the preserved CSS, so it would remove only classes that are not addressed in preserved CSS.

For example:

<style>
.c1 { color: blue; }
.c1:hover { color: red }
.c2 { color: blue; }
@media (min-width: 100px) {
  .c2 { color: red }
}
.c3: { color: blue; }
</style>
<a class="c1">c1</a>
<a class="c2">c2</a>
<a class="c3">c3</a>

would result:

<style>
.c1:hover { color: red }
@media (min-width: 100px) {
  .c2 { color: red }
}
</style>
<a class="c1" style="color: blue;">c1</a>
<a class="c2" style="color: blue;">c2</a>
<a style="color: blue;">c3</a>

Thank you.