Updated mac-side drivers

[Samuel Rydh]

I've made some changes to the mac-side MOL drivers. Anyone building MOL
from the BitKeeper repository or the rsync mirror should perform
a 'make libimport' to get the latest binaries. (An alternative
is of course to compile the mac-side drivers directly in MacOS/MacOS X.)

I would appreciate some testing of the latest code. 
Some of the changes:

- Fully asynchronous block driver
- Ejectable CD support (put 'blkdev: /dev/cdrom -cd' in /etc/mol/molrc.macos)
- Rewritten sound driver (doesn't monopolize /dev/dsp)
- Reduced interrupt latency
- Couple of bug fixes

MOL in MacOS X mode still does not support ejectable CD or sound. It shouldn't
take long to implement this though now that the proper infrastructure
is in place.

Note: Remember to replace the old MOLAudio extension with the new one.

/Samuel



Btw. All the mac-side drivers are now in the mol-drivers BitKeeper tree.