SciDAVis - Improvements SVN-temp

- Modified the scale picker so that the resize/move mode is enabled only when the user clicks on the area containing the ticks and the backbone of the scale.

- worked on the German translation

- Split out parts of CanvasPicker and Graph into tool classes (see PlotToolInterface).
- Fixed crashes upon deleting plot markers.
- Several files converted to DOS line endings.
- Minor changes to the build system; intended to improve integration into Linux distributions.

-Partially solves Bug #10806: When the opj file has zeros on some cells then qtiplot import them with empty cells. Now zeros are allways imported correctly, but sometimes empty cells are also interpreted as zeros (liborigin problem?).
- Did some cleaning to the code (includes, private/public declarations, etc...)

Small code clean-up.

- Improved drawing of scale tics in 2D plots.

- Splitted "fitclasse" into several new files and removed it from SVN.

Implemented Feature Request #3307: Integrate functions in Plots.

- Fixed printing of Pie plots.
- Fixed exporting to vector formats for 3D et 2D plots. Added the PS format as an export option.
- Added an export to PDF action button.
- Fixed bugs in FitDialog.
- Fixed bug in reading recent project files list from user settings.

- hopefully found the best solution for the problem
described in rev 412
- fixed crash in differentiation function