Added & cleaned up messages relating to a given user not existing

The following pages now have a <title> that can be set in localizations:

 * /user/USER_DOES_NOT_EXIST
 * /user/USER_DOES_NOT_EXIST/diary
 * /user/USER_DOES_NOT_EXIST/traces
 * /message/*/ID_DOES_NOT_EXIST

In addition I've cleaned up the i18n message keys of all the
''no_such_user.rhtml'' pages involved. They now all use
title/heading/body for the <title>, <h2> and <p> respectively. And the
message key {{user}} instead of {{name}}.

app/controllers/diary_entry_controller.rb

@@ -63,6 +63,7 @@ class DiaryEntryController < ApplicationController
                                           :order => 'created_at DESC',
                                           :per_page => 20)
       else
+        @title = t'diary_entry.no_such_user.title'
         @not_found_user = params[:display_name]
 
         render :action => 'no_such_user', :status => :not_found

app/controllers/message_controller.rb

@@ -29,6 +29,7 @@ class MessageController < ApplicationController
       @title = params[:title]
     end
   rescue ActiveRecord::RecordNotFound
+    @title = t'message.no_such_user.title'
     render :action => 'no_such_user', :status => :not_found
   end
 
@@ -40,6 +41,7 @@ class MessageController < ApplicationController
     @to_user = User.find(message.from_user_id)
     render :action => 'new'
   rescue ActiveRecord::RecordNotFound
+    @title = t'message.no_such_user.title'
     render :action => 'no_such_user', :status => :not_found
   end
 
@@ -50,6 +52,7 @@ class MessageController < ApplicationController
     @message.message_read = true if @message.to_user_id == @user.id
     @message.save
   rescue ActiveRecord::RecordNotFound
+    @title = t'message.no_such_user.title'
     render :action => 'no_such_user', :status => :not_found
   end
 
@@ -90,6 +93,7 @@ class MessageController < ApplicationController
       end
     end
   rescue ActiveRecord::RecordNotFound
+    @title = t'message.no_such_user.title'
     render :action => 'no_such_user', :status => :not_found
   end
 end

app/controllers/trace_controller.rb

@@ -18,6 +18,7 @@ class TraceController < ApplicationController
     if target_user.nil? and !display_name.blank?
       target_user = User.find(:first, :conditions => [ "visible = ? and display_name = ?", true, display_name])
       if target_user.nil?
+        @title = t'trace.no_such_user.title'
         @not_found_user = display_name
         render :action => 'no_such_user', :status => :not_found
         return

app/controllers/user_controller.rb

@@ -251,6 +251,7 @@ class UserController < ApplicationController
     if @this_user
       @title = @this_user.display_name
     else
+      @title = t 'user.no_such_user.title'
       @not_found_user = params[:display_name]
       render :action => 'no_such_user', :status => :not_found
     end