Function: znorder
Section: number_theoretical
C-Name: znorder
Prototype: GDG
Help: znorder(x,{o}): order of the integermod x in (Z/nZ)*. Optional o is
 assumed to be a multiple of the order.
Description:
 (gen):int             order($1)
 (gen,):int            order($1)
 (gen,int):int         znorder($1, $2)

