Report an error when trying to define ports

'v', 'vd', 'i', and 'id' as 'inout'
Parch 105 provided by  Giles Atkinson

src/xspice/cmpp/ifs_yacc.y

@@ -221,6 +221,11 @@ static void check_port_type_direction (Dir_t dir, Port_Type_t port_type)
    case DIFF_VOLTAGE:
    case CURRENT:
    case DIFF_CURRENT:
+      if (dir == CMPP_INOUT) {
+         yyerror ("Port types `v', `vd', `i', `id' are not valid for `inout' ports");
+         ifs_num_errors++;
+      }
+       break;
    case DIGITAL:
    case USER_DEFINED:
       /*