fdo77985 Calc function NETWORKDAYS

Hi Eike, all,

Calc function NETWORKDAYS is an add-in function and compatible with Excel's function NETWORKDAYS, 
but _not_ with Oasis ODFF 1.2 
(http://docs.oasis-open.org/office/v1.2/cos01/OpenDocument-v1.2-cos01-part2.html#__RefHeading__1018198_715980110)
 .

My first impression is that I could tweak the current code and make the function compatible with 
both.
For Excel the 3rd argument is a reference to a (range of) date, for ODFF it is a (reference to) 
matrix of 0 and 1. That means I can distinguish between the two. That distinction is important when 
exporting to Excel, too.

Do you think this is worth trying? Or would you prefer two internal functions, one regular in 
ScInterpreter (new, but using code from ScInterpreter::ScNetWorkdays_MS()) and one add-in 
(existing)? In that case I would need some hints where to make the switch from NETWORKDAYS in the 
cell (UI or file) and the two internal functions.


Winfried