Qix ProDOS update

[Steve Nickolas <usotsuki@buric.co>]

The old version of the disk is still here because it might still be of 
use and is still the preferred version.

http://1.buric.co/qix4-5.zip

"qix4.dsk" is the same as the old "qix8.dsk"

"qix5.dsk" contains workarounds for 2 potential problems with the old 
version:

  1. When run from BASIC a program like this will typically fail hard
     because BASIC resets the prefix to null by default. This version
     detects this and sets prefix to the root of the current drive as
     ProDOS sees it.
  2. Some launchers, like Selextra, as well as BASIC.SYSTEM, will not
     load a file that takes memory all the way up to $B09A.  A wedge,
     relocating to $0800, takes care of the loading of the first huge
     file, which then takes over and loads the rest.

However, as it is a test for Nosys and Selextra, it doesn't autolaunch, so 
I don't want to make it the standard version.  The launch file is named
QIXSTARTER (you can find this by running the CAT program also on the 
disk).

-uso.