Update all cookbooks if Berksfile, Cheffile, etc. have changed

[mlafeldt]

If the current folder is a cookbook and its dependencies have already been resolved, only this cookbook will be updated with rsync. While this is much faster than running e.g. Berkshelf, the directory resolver should only be used if no updates to Berksfile, Cheffile, etc. have been made. At the moment, the only workaround is to delete .chef-runner.

This could be fixed by writing a timestamp file and comparing that to the timestamp of all files that are dependencies.