search: allow all metatags to be negated.

Fix not being able to negate the following metatags:

* id (didn't support ranges)
* md5
* width
* height
* mpixels
* ratio
* score
* favcount
* filesize
* date
* age
* tagcount
* pixiv

config/danbooru_default_config.rb

@@ -109,7 +109,7 @@ module Danbooru
 
     # Return true if the given tag shouldn't count against the user's tag search limit.
     def is_unlimited_tag?(term)
-      term.type == :metatag && term.name.in?(%w[-status status rating limit])
+      term.type == :metatag && term.name.in?(%w[status rating limit])
     end
 
     # After this many pages, the paginator will switch to sequential mode.