More order_dialog work
More order_dialog work

* Consolidate all per-order pubmarine subscription ids into a single
  dict.  This allows for programmatic clearing of all subscription ids
  which makes the job of extending the OrderDialog easier.
* Make use of our urwid_fix RadioButton and CheckBox so we can use
  postchange to validate entries.
* Move ship and warehouse events to the CargoOrderDialog
* Move validating the quantity into its own method, independent of
  handlers.  This gets reused by multiple handlers as money, space,
  price changes, etc can all affect the maximum quantity.
* Prevent both the hold and warehouse checkboxees from being unselected
  in the CargoOrderDialog

abadger/stellarmagnate