Automatically strip marks when inserted in a place where they aren't allowed
Automatically strip marks when inserted in a place where they aren't allowed

Closes #358

kiejo/prosemirror,salzhrani/prosemirror,tzuhsiulin/prosemirror,tzuhsiulin/prosemirror,kiejo/prosemirror,salzhrani/prosemirror,kiejo/prosemirror,salzhrani/prosemirror,tzuhsiulin/prosemirror