search: change behavior of disapproval:<reason> metatag.

* Change the `disapproval:<reason>` metatag to `disapproved:<reason>`.

* Change `disapproved:<reason>` to show all posts disapproved for a
  given reason, not just those disapproved by the current user.

* Allow searching for your own disapprovals with `disapproved:<my_name>`.

* Drop the `disapproved:<any|none>` metatags. `disapproved:any` is
  equivalent to `disapproved:<my_name>` and `disapproved:none` is
  equivalent to `-disapproved:<my_name>`.

These changes are so that you can search e.g. disapproved:poor_quality
to find all posts disapproved for poor quality.

app/javascript/src/javascripts/autocomplete.js.erb

@@ -117,7 +117,7 @@ Autocomplete.initialize_tag_autocomplete = function() {
       case "child":
       case "parent":
       case "filetype":
-      case "disapproval":
+      case "disapproved":
       case "embedded":
         results = Autocomplete.static_metatag_source(term, metatag);
         break;
@@ -286,8 +286,8 @@ Autocomplete.static_metatags = {
   filetype: [
     "jpg", "png", "gif", "swf", "zip", "webm", "mp4"
   ],
-  disapproval: [
-    "any", "none", "disinterest", "poor_quality", "breaks_rules"
+  disapproved: [
+    "disinterest", "poor_quality", "breaks_rules"
   ]
 }