SciDAVis - Improvements SVN-temp

- updated the German translation

Added fileDialogs.cpp

- fixed a conversion error in scaleDraws.h
- fixed qwt.pro to make QtiPlot compile in unix enviroments
- removed a connection to a non-existing signal in application.cpp

Added Qwt5 files (some old files from Qwt 4.2.0 need to be deleted)

- Improved the lineDialog, using a suggestion from an old patch from Knut: coordinates can be now displayed in pixels or in scale coordinates.
- Fixed a table context menu bug and improved (patch from Shen Chen).
- Added the possibility to change the canvas background color.

Still TO DO: fix export to SVG and to EPS!

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).