add foreach_bit function to call a functor with all the set bits in a mask
add foreach_bit function to call a functor with all the set bits in a mask

chr-engwer/Vc,VcDevel/Vc,chr-engwer/Vc,VcDevel/Vc,VcDevel/Vc,chr-engwer/Vc,VcDevel/Vc