Copy method of activation doesn't work on some systems

[vlascik]

Copy method of activation doesn't work on some systems (busybox based, e.g. boot2docker/docker-machine), whose cp doesn't support -T parameter, the command then fails. I think the line 107 of index.js should just be:

linkCmd = 'cp -R ' + activeRevisionPath + ' ' + activationDestination;

[arenoir]

@vlascik thanks for logging the issue... I am thinking there should be a cpFlags config option.