Fix #13741. Make wrap/unwrap methods optional. Close gh-1222.
Fix #13721. Filter before .remove() loop so positionals work. Close gh-1221.
Improve CSS and `Support:` comments. Close gh-1220.

1) corrected box-sizing rules order - the unprefixed value should always be the last one
2) removed last semi-colons in CSS rules
3) updated support comments

code review changes + more consistent comment spacing