[fluxus] build error: PDataArithmetic.cpp

[nik at fo.am]

The recent changes to pdata in cvs give the following build error on osX
(ie. gcc 4.0)

PDataArithmetic.cpp:172: error: specialization of 'template<class S, class
T> static fluxus::PData*
fluxus::ClosestOperator::Operate(fluxus::TypedPData<S>*, T)' in different
namespace

PDataArithmetic.h:129: error:   from definition of 'template<class S,
class T> static fluxus::PData*
fluxus::ClosestOperator::Operate(fluxus::TypedPData<S>*, T)'