- remove LoadPreferences() function, make use of SetKey instead
- lazily create accounts/identities/servers are they are requested
- request pref service inside each object rather than passing the same service around
- start to support upgrading of preferences from 4.x world
- preference accessors ask prefs store directly instead of trying to maintain their own copy of each preference
- start to add support for shadow/default "fallback" account/server prefs