Cowshed 1.4 - Background colour behind SHELL result strings

All versions of COWSHED.EXE has been compiled with QuickBasic 4.5 before.

COWSHED.EXE lists the settings using SHELL result included in QuickBasic (Shell "config -get ...") near the description on the screen.

When using DOSBox Staging, the result of the DOSBox command "MIXER" will be displayed now as if written from within the Command shell.

On non-black background colours, the listings will be displayed on the correct background colour now.

Some DOSBox ports, including the original SVN version writes QuickBasic SHELL result strings on a black background. This is not expected if the background colour of the screen is not black.

Technically, COWSHED.EXE replaces the background colour by the correct one, if a black background colour is detected behind the SHELL result. This will take a while, so set the frameskip rate to a higher value now before running this application.

Second fix is recognizing mounted drives.