Added a better mechanism for calculating when content was last modified for cache headers.

lib/WebGUI/Asset/Post.pm

@@ -324,12 +324,6 @@ sub formatContent {
         return $msg;
 }
 
-#-------------------------------------------------------------------
-# Too slow to try to find out children, just always assume new data
-sub getContentLastModified {
-    return time();
-}
-
 #-------------------------------------------------------------------
 sub getAutoCommitWorkflowId {
     my $self = shift;