+20180428
+ + document new form-extension O_EDGE_INSERT_STAY (report by Leon
+ Winter).
+ + correct error-returns listed in manual pages for a few form functions
+ (report by Leon Winter).
+ + add a check in form-library for null-pointer dereference:
+ unfocus_current_field (form);
+ form_driver (form, REQ_VALIDATION);
+ (patch by Leon Winter).
+
+20180414
+ + modify form library to optionally delay cursor movement on a field
+ edge/boundary (patch by Leon Winter).
+ + modify form library to avoid unnecessary update of cursor position in
+ non-public fields (patch by Leon Winter).
+ + remove unused _nc_import_termtype2() function.
+ + also add/improve null-pointer checks in other places
+ + add a null-pointer check in _nc_parse_entry to handle an error when
+ a use-name is invalid syntax (report by Chung-Yi Lin).
+