Issue 309 - Use Shadow DOM if available to don't mess with web pages that rely on the order of their own <style> tags

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extra : rebase_source : e7ed556991874f7b778d866644baa9e2928d975a
Issue 309 - Don't insert <style> tag if there are no element hiding rules.

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extra : rebase_source : 83d669407e8ed3debd6219f0b5b9215090cbe22c