Adds a setting to cache textile rendering (off by default).

* it uses ActionController cache store which is MemoryStore by default and can be configured with config.action_controller.cache_store
* macro processing was moved out of textile rendering so that it doesn't get cached
* no noticeable improvement is expected for small portions of text, so only texts larger than 2KB are cached

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@3372 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/settings/_general.rhtml

@@ -20,6 +20,8 @@
 
 <p><%= setting_select :text_formatting, Redmine::WikiFormatting.format_names.collect{|name| [name, name.to_s]}, :blank => :label_none %></p>
 
+<p><%= setting_check_box :cache_formatted_text %></p>
+
 <p><%= setting_select :wiki_compression, [['Gzip', 'gzip']], :blank => :label_none %></p>
 
 <p><%= setting_text_field :feeds_limit, :size => 6 %></p>