SciDAVis - Improvements SVN-temp

- Fixed crash when double-clicking on a selected Line or Text Marker.
- Tried to improve tab focus on 2D plot markers, still buggy!

add spreadsheet's properties import from OPJ(v.7.5): labels, formulas, formats, widths; hidden and loose datasets

- Fixed 2D plot curves context menu.

- Fixed crash when removing curves from 2D plots.
- Renamed some 2D plots export functions for a more unitary naming scheme.

- fixed a typo in ApplicationWindow
- finished the German translation

- 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.