Move GtkWrapMode from GtkTextTag to the GtkTextView section. The wrap
mode property is in the text view.
Links to the "mark-set" and "mark-deleted" signals.
Add a precision about gtk_text_buffer_get_iter_at_line().
Fix typo in gtk_text_tag_set_priority().
https://bugzilla.gnome.org/show_bug.cgi?id=708076