custom css: don't add !important to every line.

Fixes #4398.

app/controllers/users_controller.rb

@@ -109,7 +109,7 @@ class UsersController < ApplicationController
   end
 
   def custom_style
-    @css = CustomCss.parse(CurrentUser.user.custom_style)
+    @css = CurrentUser.user.custom_style
     expires_in 10.years
   end
 

app/logical/custom_css.rb

@@ -1,11 +0,0 @@
-module CustomCss
-  def self.parse(css)
-    css.to_s.split(/\r\n|\r|\n/).map do |line|
-      if line =~ /\A@import/
-        line
-      else
-        line.gsub(/([^[:space:]])[[:space:]]*(?:!important)?[[:space:]]*(;|})/, "\\1 !important\\2")
-      end
-    end.join("\n")
-  end
-end