Merge pull request +6326 from c9/fix-retina

add missing retina buttons

package.json

@@ -60,7 +60,7 @@
         "c9.ide.language.javascript.tern": "#a65ad88dd9",
         "c9.ide.language.javascript.infer": "#ebb2daf81a",
         "c9.ide.language.jsonalyzer": "#5262f6b4b9",
-        "c9.ide.collab": "#a75ffca258",
+        "c9.ide.collab": "#51b8b72e0f",
         "c9.ide.local": "#2bfd7ff051",
         "c9.ide.find": "#989c06e6a7",
         "c9.ide.find.infiles": "#28b3cfcb47",