[PUSHED] adding calc add-in for option pricing

[tino]

> Seeing this commit, I note that XPricingFunctions has method
> identifiers starting with a lower case letter and containing
> underscores.  Such identifiers are reserved to the UNO
> implementation.  (See
> <http://www.openoffice.org/udk/common/man/typesystem.html>.  There

Sorry, UNO has been too complex for me to really understand. :)
Do you mean function names like getOpt_barrier() or input variables as
put_call or both? If it's the function names then would
getOpt_barrier() --> getOptBarrier() be ok?