[category-group-discussion] Added paging to group discussions listing.
[template_static_front_page] added safegurard for mxpress_options['doHideHomeContent'].
[template_single_post] Added logic to point back link to post category.
[mxpress_comments] Added logic to point back link to post category.
[functions_content_filtering] Added safeguard for mxpress_opstions indexing.