Also cache children for notes and links for smaller page ranges, as assistive devices can request the children several times in a row. Invalidate in some more cases, eg when changing displaymode.
Also cache children for notes and links for smaller page ranges, as assistive devices can request the children several times in a row. Invalidate in some more cases, eg when changing displaymode.

git-svn-id: cb3fc60f0f557b927b8032d8a94e869b6f9f230b@3794 0fceea05-a30d-0410-8a8b-80ef821fb0a1

jasongrout/skim,camillobruni/skim,camillobruni/skim,jasongrout/skim,camillobruni/skim,camillobruni/skim