The MutableContent change probably makes more sense on o.a.s.gadgets.Gadget. Everything else looks good
http://codereview.appspot.com/20043/diff/1/4 File java/gadgets/src/main/java/org/apache/shindig/gadgets/rewrite/MutableContent.java (right): http://codereview.appspot.com/20043/diff/1/4#newcode165 Line 165: public void addFeature(String name) { Gadget is probably a better home for this http://codereview.appspot.com/20043/diff/1/4#newcode183 Line 183: return ImmutableSet.<String>of(); Collections.emptySet ? http://codereview.appspot.com/20043
