Can't remove bold and italic when list was created on b/i text

[pilz]

Steps to reproduce:

• Write text
• Make it bold and italic
• out of that text, start a bullet list
• Write some text in the first bullet item
• Try to remove the bold or italic formatting

Neither of both can be removed. In inspector I see raptor using exchangably the i and b tags or em.cms-italic or strong.cms-bold.

Maybe related to #183 ?