The pointer passing for display options is deprecated. This removes the
excess casting as the EDA_FRAME didn't need the base call with no value.
All requests for display options are now returned const and are updated
with a Set() routine after modification.
In Gerbview, this resolves an issue where the display options were not
stored because it was receiving the NULL from EDA_FRAME.
This parameter defines the working area (full page) size.
The fix is not perfect, because it does not take in account the page size.
However it is similar to the "old" initialization, before Eeschema GAL.
In Eeschema, a reasonable boundary size is used.