Decouple scan_len from co. Sometimes we must use scan_len instead of co...
Since zx_emul has co=40 but scan_len=48 this is necessary.
Now zx_emul displays everything correctly except for some annoying vertical bars
I couldn't get rid off.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@487 7758b857-130e-0410-ab9c-d8735a528d18