!important should be preserved in inline styles

[seb303]

Sometimes it is necessary to have inline styles include !important. For example to remove link underlining in Windows 10 Mail.

However, it seems that Emogrifier drops the !important when inlining the styles. I understand this may be necessary for pseudo-class overrides to work, so it's probably a good default behaviour. But could there be an option added to allow it to be preserved?