Fix a bug in loupe move handler.
Fix a bug in loupe move handler.

dillan/mapsense.js,mbostock/polymaps,manueltimita/mapsense.js,shkfnly/mapsense.js,Laurian/mapsense.js,cksachdev/mapsense.js,Andrey-Pavlov/polymaps,Cherchercher/polymaps,AndBicScadMedia/polymaps,sfchronicle/mapsense.js,gimlids/mapsense.js,Andrey-Pavlov/polymaps,simplegeo/polymaps,RavishankarDuMCA10/mapsense.js,makinacorpus/polymaps,mapsense/mapsense.js