SciDAVis - Improvements SVN-temp

various improvements to the documentation of the new classes

- Documented col("name"), tablecol(), sr and er.
- Documented recalculation of cells.
- Added cell(), col() and tablecol() to the list of functions supported with muParser.
- Removed superfluous file commands.docbook

- committing the column data classes that now follow
the new data source concept as discussed with Knut

- Small code cleanup

- Fixed possible bug with large comment and labels

- Added function tablecol(<table name>,<column name or number>) for Python and muParser.
- Added Python hack to allow table(<table name>).col(<column name or number>).
Both of these only work when used within the context of a Table.

Appending a project as a new folder is now also possible from the "Open Project" dialog.

- Simplified import of ASCII files.
- Added ExtensibleFileDialog, a generic extension mechanism for QFileDialog.

- Fixed table import with current locale

Fixed bug in Table::importASCII(), due to the behavior of QTextStream regarding end-of-line character, which is problematic for reading Mac OS X generated ASCII files.