SciDAVis - Improvements SVN-temp

- Fixes bugs 010440, 010320 and 010154.

- Improved the export of 2D plots.
- Fixed a small bug concerning the restoring of notes from project files.

Minor fixes to moving layers and markers.

- Improved the ImageDialog by replacing the ChainButton with a simple QCheckBox.
- Removed some obsolete code from MultiLayer class: this also prevents flickering when selecting objects on a plot.

- Fixed bugs in InterpolationDialog, added the interpolation operation to the Python interface and fixed bug #10169.
- Improved setColor() method in Fitter.cpp.
- Fixed resizing of MDI windows through the ImageDialog.
- Improved the layout of the ImageDialog.
- Improved the sorting of single columns in Tables: now text columns are also sorted.

- Dropped support for SIP < 4.4, which is not even supported by PyQt4.
- Sorting of table columns slightly improved and added to qti.sip.
- Fixed ScriptWindow (the setVisible() signal was masking QWidget::setVisible()).
- Some minor fixes and improvements.

- Selection, moving and resizing of layers and plot markers rewritten.
- Reverted some changes of r341 that broke positioning of image markers.
- Some documentation added.
- Removed superfluous include from muParserScripting.cpp.

- Improved the sorting of tables and added support for some of the sorting operations to the scripting interface.
- Fixed a small bug in the Fitter class.

- Improves the SortDialog class and fixes bug #10289;
- Restores the "new_matrix" icon accidentaly replaced during my last commits.
- Improved the layout of the AssociationsDialog.

- Added documentation and notes about future plans at various points.
- Added a documentation page about coding style guidelines.
- Several minor fixes and improvements.