SciDAVis - Improvements SVN-temp

- worked on integrating Table into the aspect framework
(a lot of table functionality is disabled at the moment)

- moved all test programs/unit tests to "tests" folder

- added handlers for column signals to TableModel
- extended the table test program

- updated the doxygen documentation for several classes
according to the latest changes
- added some missing code (mainly in the filter classes)

- worked a little bit on TableModel and TableTest

- renamed AspectModel to AspectPrivate and modified all
aspect commands to work on AspectPrivate only (analogous to
Column and ColumnPrivate)
Reason: IMO, AspectModel does not qualify as a model in the
MVC or MVP paradigm because it (or the commands) must know
the owner and there is not view for it

- worked a lot on the aspect framework and its integration with Column:
* unified some class/method/member names
* unified change notifications: removed the observer pattern in
favor of signals/slots connections
* shared_ptr is now used for memory management of aspects, columns, and filters
* column commands now operate on ColumnPrivate only (following the model
that the commands are really between Column and ColumnPrivate)
* all abstract classes use a wrapper for signals and slots, this
avoids the need to have QObject as a base class and prevents
multiple inheritance problems
* test status: aspect-test runs and column-test is passed w/o error
* known issues: some doxygen comments need to be updated to
the current implementation; some aspect related methods
are not yet properly implemented in the filter classes

- removed the old column classes
- fixed some bugs in Column and AbstractAspect
- modified TableModel to use Column instead of AbstractColumnData
- started writing a test program for the table classes

- modified AbstractAspect to not inherit from QObject but
keep its functionality
- fixed the aspect test

- finished the Column unit test to the point I planned it
- fixed the rest of the bugs I could find in Column and
related classes
- added SimpleCopyThroughFilter (input and output
filters of columns are AbstractSimpleFilters instead
of AbstractFilters now)