List of items to consider for Kst2 - mostly because they break backwards
compatibility or require hacks right now:

- Make data sources also data writers so we can save to formats other than
  ASCII.
- Clean up data types for plugins.
- rework update() to be two functions, one which does the "infrastructure" part
  and one which is reimplemented to do the things specific to each type of
  object
- move isValid() up to KstObject so that KstVector can use it 
- remove duplicated tagNames() (the non-const one) from KstObject and make the
  const one virtual
- kstdatasource.cpp : configWidget() needs to be non-const
- kstdatasource.cpp : obtainFile() needs to take a widget
- KstObject: setDirty(bool) needs to be virtual.  Maybe also dirty()
- Rename rwlock.h to avoid global namespace issues
- data sources: fix the load/create/save mess

