Prevent adding custom CSS multiple times.

src/General/lib/$.coffee

@@ -114,11 +114,11 @@ $.asap = (test, cb) ->
   else
     setTimeout $.asap, 25, test, cb
 
-$.addStyle = (css, id) ->
+$.addStyle = (css, id, test) ->
   style = $.el 'style',
     id: id
     textContent: css
-  $.asap (-> d.head), ->
+  $.asap (-> d.head and (!test? or test())), ->
     $.add d.head, style
   style
 

src/Miscellaneous/CustomCSS.coffee

@@ -3,8 +3,7 @@ CustomCSS =
     return unless Conf['Custom CSS']
     @addStyle()
   addStyle: ->
-    $.asap (-> $.id 'fourchanx-css'), =>
-      @style = $.addStyle Conf['usercss'], 'custom-css'
+    @style = $.addStyle Conf['usercss'], 'custom-css', -> $.id 'fourchanx-css'
   rmStyle: ->
     if @style
       $.rm @style