mf_All.js removed _id

[1u]

id is removed in mfAll.js. but linked object with this same id remains in collection.
randomly searching, sorry... (tell me if it's annoying :)

same commit: (Openki/Openki@f2f9e67)

     "course.edit.groupUnlistingError": {
-      "_id": "CT4xcjqjH7ZdScT5Y",
       "key": "course.edit.groupUnlistingError",
       "lang": "en",
       "text": "Unable to remove group: {ERROR}",
-      "ctime": "2015-10-14T17:05:17.000Z",
-      "mtime": "2015-10-14T17:05:17.000Z",
-      "revisionId": "KjxRu8DK8f3xLMAB8",
-      "file": "client/views/groups/groupListing.js",
-      "line": 37,
-      "func": "function(err)"
+      "ctime": 1464642609000,
+      "mtime": 1464704870979,
+      "revisionId": "LE4kssXimP2ZyS7hn",
+      "file": "client/views/groups/listing/groupListing.js",
+      "line": 38,
+      "template": "unknown",
+      "removed": true
+    },

why is it removed and what happens if key is added again?

[gadicc]

Yeah, this is correct; we no longer rely on the _id for uniqueness, rather the combination of key and lang. This makes it a lot easier to sync between dev and production where the _id might be different.

[gadicc]

Let me track this with the order in #233.