Update-modules: do not use bower -f to avoid unnecessary work
Update-modules: do not use bower -f to avoid unnecessary work

Currently, our cron jobs downloads all our puppet envs every minute, which is kind of useless and heavy.
Try to avoid that by:

1) running bower prune, to remove old modules, before installing (hoping to emulate bower -f install well enough)
2) removing -f from bower install & update, use --force-latest to "fix" conflicts instead
3) setting CI mode on for bower

TomiTakussaari/bower_puppet_server,TomiTakussaari/bower_puppet_server