Add extensions and targetExtensions option
Add extensions and targetExtensions option

jcope2013/broccoli-persistent-filter,chadhietala/broccoli-persistent-filter,stefanpenner/broccoli-persistent-filter,chadhietala/broccoli-filter,stefanpenner/broccoli-filter,rwjblue/broccoli-persistent-filter,broccolijs/broccoli-filter,joliss/broccoli-filter,csantero/broccoli-persistent-filter