Editing document with many (~1k) connectors eats all available CPU
power as every spellchecking event locks and then unlocks SdrModel
which in turn repositions ALL connectors in entire document, so let's
not do that

Additionally, set OutlinerParaObject and broadcast only when something
has actually changed

Change-Id: I647b7309729dce153b8e05eff4677fe7bb9840a7
Reviewed-on: https://gerrit.libreoffice.org/49995Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>