Fix for instance pool size() function.
Fix for instance pool size() function.

radarsat1/libmapper,radarsat1/libmapper,radarsat1/libmapper,malloch/libmapper,malloch/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,malloch/libmapper,libmapper/libmapper,libmapper/libmapper,radarsat1/libmapper,libmapper/libmapper,radarsat1/libmapper,libmapper/libmapper,malloch/libmapper,malloch/libmapper