curses 'perm_invent' fixes

curses 'perm_invent' fixes

I noticed the wrapping issue while testing out the 'bad fruit' fix,
then the other things while fixing it.

1) inventory entries too wide for narrow persistent inventory window
   wrapped without any control; normally can't be seen except for the
   last entry when the list is short enough to leave at least one line
   available; it looked fairly reasonable with window borders Off, but
   when On the last char of the first line and first char of second
   line were clobbered by the border box;
2) when there were too many entries to fit within the height, those
   after the last one which fit were appended to it for borders Off
   (or written on bottom line and then overwritten by the border box
   for borders On); noticed because the selector letter is highlighted
   with inverse video, even when written at an unexpected place;
3) suppress the inverse video hightlighting of inventory letters since
   they can't be selected from that 'menu';
4) for borders Off, the top line was left blank as if a border was
   going to be drawn there;
5) since the entries are truncated due to the narrow window (on a
   modest sized display), strip off leading "a", "an", or "the" prefix
   for inventory entries (written to curses perm_invent window only);
   lets a couple more characters of more interesting stuff be seen.