[Len Case]

* less crashiness is an estimate across crashes reported in sp6--no warrantee expressed or implied :)

This should fix the crash when modifying site preferences (global or site-specific).

Additionally, we now disable the Adobe PDF Viewer plugin by default since it only works in Safari. (See "Preferences -> Plugins").

There are some minor other changes to UI--but the crashes are the main reason for the new release.