Fixed a defect in iosrv.exe that caused a panic if a foreground read object was attached to a different end point.
This was due to the read object being notified of a change in foreground before its iEndPoint member was updated. This member is now updated before attempting the attach, and is set to NULL in the event of a leave (resulting in the read object being left in an unattached state).
Also tweaked ymodem.cif to make it more readable.