Pin socket.io version to 1.4.7.
Pin socket.io version to 1.4.7.

What appears to be a change in a downstream dependency of socket.io
version 1.4.8 breaks IE <= 9.

testem/testem,bradleylandis/testem,bradleylandis/testem,paulot/testem,paulot/testem,paulot/testem,bradleylandis/testem,johanneswuerbach/testem,johanneswuerbach/testem,johanneswuerbach/testem,testem/testem,testem/testem