Loading tags from file does not set callbacks

[phastmike]

Not setting up callback handlers for tags originated from tags file. Need to set them. Work has been delegated to tags_treeview (window :: load_tags) but must be refactored.

[phastmike]

code in window.add_tag:

                tag.enable_changed.connect ((enabled) => {
                    lines_treeview.line_store_filter.refilter ();
                });

                tags_treeview.add_tag (tag);
                if (lines_treeview.hide_untagged) { 
                    lines_treeview.line_store_filter.refilter ();
                }
                count_tag_hits ();