Hacked some column sorting onto RatesController

* Added SortHelper to RatesController
* Init and updating the sorting (pre 0.8 sort_update)
* RatesController#index will only render the layout on non-xhr requests
* Changed Rate.history_for_user to take an order clause
* Added rate_sort_header_tag and rate_sort_link to the SortHelper in order
  to get the correct parameters for sorting Rates
* Added rate_sort_header_tags to the Rate lists

  #1915

lib/rate_sort_helper_patch.rb

@@ -0,0 +1,63 @@
+require_dependency 'sort_helper'
+
+module RateSortHelperPatch
+  def self.included(base) # :nodoc:
+    base.send(:include, InstanceMethods)
+  end
+  
+  module InstanceMethods
+    # Allows more parameters than the standard sort_header_tag
+    def rate_sort_header_tag(column, options = {})
+      caption = options.delete(:caption) || titleize(Inflector::humanize(column))
+      default_order = options.delete(:default_order) || 'asc'
+      options[:title]= l(:label_sort_by, "\"#{caption}\"") unless options[:title]
+      content_tag('th',
+                  rate_sort_link(column,
+                                 caption,
+                                 default_order,
+                                 { :method => options[:method], :update => options[:update], :user_id => options[:user_id] }),
+                  options)
+    end
+
+    # Allows more parameters than the standard sort_link and is hard coded to use
+    # the RatesController
+    def rate_sort_link(column, caption, default_order, options = { })
+      key, order = session[@sort_name][:key], session[@sort_name][:order]
+      if key == column
+        if order.downcase == 'asc'
+          icon = 'sort_asc.png'
+          order = 'desc'
+        else
+          icon = 'sort_desc.png'
+          order = 'asc'
+        end
+      else
+        icon = nil
+        order = default_order
+      end
+      caption = titleize(Inflector::humanize(column)) unless caption
+      
+      sort_options = { :sort_key => column, :sort_order => order}
+      # don't reuse params if filters are present
+      url_options = params.has_key?(:set_filter) ? sort_options : params.merge(sort_options)
+
+      # Hard code url to the Rates index
+      url_options[:controller] = 'rates'
+      url_options[:action] = 'index'
+      url_options[:user_id] ||= options[:user_id]
+      
+      link_to_remote(caption,
+                     {
+                       :update => options[:update] || "content",
+                       :url => url_options,
+                       :method => options[:method] || :post
+                     },
+                     {:href => url_for(url_options)}) +
+        (icon ? nbsp(2) + image_tag(icon) : '')
+    end
+    
+  end
+end
+
+SortHelper.send(:include, RateSortHelperPatch)
+