Internal renaming of elder,leader,regular,basic to numbers

Changed internals so trust levels are referred to with

TrustLevel[1], TrustLevel[2] etc.

This gives us much better flexibility naming trust levels, these names
are meant to be controlled by various communities.

spec/components/composer_messages_finder_spec.rb

@@ -107,7 +107,7 @@ describe ComposerMessagesFinder do
       end
 
       it "doesn't return notifications for new users" do
-        user.trust_level = TrustLevel.levels[:newuser]
+        user.trust_level = TrustLevel[0]
         finder.check_avatar_notification.should be_blank
       end