SciDAVis - Improvements SVN-temp

Almost finished the port to Qwt5: the only thing not working correctly is the EPS export. Testing needed.

-Ported LegendMarker and all derived QwtPlotCurves to Qwt5

-Fixes autoscaling of 2D plots.
-Improves ImageMarker and LineMarker classes: the export to EPS and SVG (only for line markers) of these objects works correctly.
-Adds a first implementation of the feature request #2304: zoom in/zoom out in images is possible now (the number of zoom in operations is limited, I don't know why yet and zooming out only restores the initial state of the image).

Fixed numerical format of axis labels.

improvements to ConfigDialog:
- the width of the itemsList is now calculated
depending on the width of its contents
- "Apply", "Ok", and "Cancel" now work like
commonly used in other applications
(e.g. "Cancel" now cancels all settings
since the last "Apply") with one exception:
the language setting

- merged changes to ConfigDialog from scripting branch
and converted them to Qt4

Fixed more stuff in the the port to Qwt5: set scale division, ticks length.

Fixed the behavior of some of the 2D plot tools: the data reader, the data range selectors, ...

-Fixed ticks behavior and a few more bugs in 2D plots due to the port to Qwt5. Still far from stable!

-First port to Qwt5 (version from CVS): a lot of features are broken, a lot of crashes still need to be fixed.
-Added export of single layers to SVG.