Merge branch '3632_widget_flags'

Merge branch '3632_widget_flags'

* 3632_widget_flags:
  Reorganize WDialog flags.
  (dlg_set_position): minor refactoring.
  Rename DLG_WANT_TAB to WOP_WANT_TAB and move it to widget_options_t.
  By default, WOP_WANT_HOTKEY option is off.
  If widget wants cursor, define that explicitly.
  Add WST_MODAL state.
  WOP_TOP_SELECT: new widget option
  Join widget_state_t and dlg_state_t.
  Move WOP_WANT_IDLE option to widget_state_t flags
  Move WOP_DISABLED option to widget_state_t flags
  widget_state_t: new type.
  (widget_get_options): new widget API.
  Change prefix of widget options: W_ -> WOP_.
  Ticket #3632: refactoring of widget flags.