eeschema: code cleaning, comments added, and the true number of sheets and sheets numbers in complex hierarchies

All: cleaning code to draw/plot texts (work in progress). Eeschema: italic and bold texts and labels allowed
(plot functions not yet updated for bold texts)

Improved grid implementation, 3D viewer debug assertion fix, moved drawpanel.cpp to common library, and added WinEDA_Appl declaration.

 + Function name on newline
 + All function parameters on newline ( the first on function name line )

Update dutch language

translation of last french comments in dialog_edit_component_in_schematic.cpp, and minor enhancements
Update french dictionnary