New features and one fix

[dorssar]

I added more new features for setting:

• page orientation (for the print setup, visible in print preview mode) [ use: ws.pageOrientation("landscape") ]
• top, bottom, header, footer, right, and left page margin [ use: ws.leftMargin(0.3) ]
• setting header and footer content [ use: ws.header("page 1 of ?", Position.RIGHT) ] [ use: ws.footer("Helix", Position.LEFT, "Arial", 10) ] [ use: ws.footer("sheetname", Position.CENTER, 8) ]
• freeze pane (some rows and columns kept still while scrolling) [ use: ws.freezePane(1, 3) to freeze the first column on the left and the top three rows ]
• shading rows (extension of shadeAlternateRows) so that each Nth row is colored [ instead of shadeAlternateRows(color), simply use: shadeRows(color, eachNRows) ]

Fixed:

• setAutoFilter (the filters were empty cause it was applied on one row only instead of automatically applied to all the header columns)

Adjust the code if needed :)