Remove annotations from the PDFView before reloading the pdf document. Hopefully this fixes some crashers, though I can't really imagine. But I don't understand why the crashes happen either. 
Remove annotations from the PDFView before reloading the pdf document. Hopefully this fixes some crashers, though I can't really imagine. But I don't understand why the crashes happen either. 

git-svn-id: 765db44a9620ed55f4f8addfd3c14fe8cd57f6bb@2449 0fceea05-a30d-0410-8a8b-80ef821fb0a1

nanoant/Skim,nanoant/Skim,nanoant/Skim,nanoant/Skim,nanoant/Skim