Fix dup content with and hooks

Created by: dentm42

This patch fixes a problem when using the $module_mod_content hook, the $arr[] where the page content in $arr['content'] is duplicated on the rendered page. Need to reset the $arr[].before calling the $module_mod_aftercontent hook.

Might want to consider also making use of the $arr['replace'] here as well in order to void the page and replace it with the results of $module_mod_aftercontent - but this patch does not take that into consideration.