Add option to disable bits

[daxgames]

Allow disable of BITS.

• Part of Prefix and proxy #179 so closing Prefix and proxy #179

Edit floppy\_packer_config.cmd:

:: Uncomment the following to disable BITS so scripts can fail instead of hanging when
:: BITS doesn't work right.
:: Default: (unset)
:: set DISABLE_BITS=1

[arizvisa]

I don't see any issues with this, it works for me, and I hate BITSADMIN anyways.

Thanks for your contribution!