Make polymaps.min.js target writeable.
Make polymaps.min.js target writeable.

I'm leaving polymaps.js read-only, so that I don't accidentally edit polymaps.js
when debugging. But when copying polymaps.min.js to another directory, it's
useful for the file to be writeable so that I don't have to cp -f.

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