Lots of changes that were tightly coupled:

1. Reorganize options related to Observing List in kstars.kcfg under a
   new group.

2. Revamp the design of the "Advanced" options section to introduce a
   Tab Widget [I need feedback on this decision]. This is so that we
   can put all the advanced options in there without any clutter. [Q:
   Does observing list belong there?]

3. Remove the hackish DSS vs. SDSS preference option in the Observing
   List view and introduce the setting in the Advanced options under
   Observing List.

CCMAIL: kstars-devel@kde.org