Add suport of print area and page setup

[drow-it]

To set print area of sheet use bool setPrintArea(const CellRange &range, const QString &sheetName=QString()); To set page scaling to percent use bool setPageSetup(double percent, QPageSize::PageSizeId size, QPageLayout::Orientation orientation); To set page scaling to number of pages use bool setPageSetup(int fitToWidth, int fitToHeight, QPageSize::PageSizeId size, QPageLayout::Orientation orientation);

Autoformatting in Qt Creator insert some extra spaces in old code, that's why so many lines has changes