propagating --cdn option to muffin watch
the sequences option for uglify2 is true by default but this was breaking the call to `window.external.notify()` (there are a couple of other documented cases: http://translate.google.ca/translate?hl=en&sl=zh-CN&u=http://www.cnblogs.com/blastmann/p/external-notify-cant-use-with-uglifyjs-compressor.html&prev=/search%3Fq%3Dwindow.external.notify%2Buglifyjs%26biw%3D1440%26bih%3D753 and http://stackoverflow.com/questions/17168408/cant-use-window-external-notify-after-uglifyjs-compressed) changing this flag to false as it produces a safer compression (albeit with the tradeoff of a slightly larger file size)