SciDAVis - Improvements SVN-temp

Improved introduction to Python scripting.

- Added visual feedback for executing code in ScriptEdit.
- Fixed a signal connection in FitDialog.

- adjusted Column, Column::Private (formerly ColumnPrivate),
and the column commands to the 5-layer model
- some minor changes to Table and related classes

Removed column label/comment in favour of aspect name/comment.

- Removed view() from AbstractAspect and introduced AbstractPart as new base
class for Aspects like Table or Notes. Other Aspects may wish to define their
own types of and protocols for views. AbstractPart also handles parts of the
context menu, meaning that it no longer needs to be patched together from two
sources.
- TODO: The new context menus allow columns to be removed from their table via
the project explorer. Some way of updating Table's internal state accordingly
has to be found.
- Added experimental module interfaces. This is supposed to keep the kernel
manageable by splitting out, for example, all table-related code into a
module. Also, after maturing through a couple of releases, these interfaces
may provide the basis of a plugin API.
- Added modular .pro files to go with the module concept.
- Moved creation of undo/redo actions to AbstractAspect in order to avoid code
duplication. TODO: make keyboard shortcuts customizable; probably by using
a Settings singleton for global (i.e., not project-specific) settings.
- Removed "Hide or remove?" question on closing MDI windows.
- Added documentation on the Aspect framework and the 5-layer-model it uses.
Documentation in "related pages" moved to separate files in doc/.
- Some progress made on AbstractFit.

- small update to the web page :-)

- ported Table, TableView, TableModel and all table
commands to the 5 layer model
- added class Table::Private
- removed the table formula editor (this was more or less
only a test; comfortable formula editing could later be
implemented in TableItemDelegate)
still TODO for these classes:
- rewrite AspectView (remove QMdiSubWindow as base class etc.)
and adjust TableView accordingly
- fix context menu in TableView
- table-test does not compile yet

- eliminated shared_ptr from column-test
- fixed a bug related to Column::setColumnMode() and
addition of input/output filters as child aspects
(this is now done from within ColumnPrivate, otherwise
the column commands cannot change the input/output filters)
- fixed a bug when changing the column mode from Date/Time to
DateTime
- still TODO: another assertion in column-test

- Made AbstractAspect a subclass of QObject. AbstractColumn and AbstractFilter
now inherit from AbstractAspect, so that we don't need any
signal-emitter/reciever classes any more.
- Since filters are now Aspects, their ownership can be managed by the
generic mechanisms in AbstractAspect. TODO: implement hiding of Aspects
most users don't need to know about, like input/output filters of columns.
- Eliminated shared_ptr in favour of the hierarchy-based memory management
provided by AbstractAspect.

- Fixed encapsulation breaches in AbstractAspect - only undo-aware methods
should be exposed. This does mean that Table has to be careful about not
triggering calls into the AbstractAspect API within its undo commands, but
it (hopefully) makes the undo system more robust.
- Removed #includes <QXmlStreamReader> and <QXmlStreamWriter> from
AbstractAspect.h, since it will be included quite often (directly or
indirectly), not always in conjunction with XML handling.