lxdream WIP - GD-rom and ALSA improvements

What's going on with the Sega Dreamcast emulator for Linux.

From the official website:

Updated the CD-Rom image code to handle the various read modes (Bug #59), including raw reads (using libedc to generate the EDC/ECC data on the fly), as opposed to the old code which really only handled mode 1 and mode 2 form 1 sectors - CD-Roms are much more complicated beasties than one typically imagines. I haven’t validated it yet, but I don’t think I’ve broken any of the cases that previously worked either *crosses fingers*.

In other news bhaal22 has contributed an ALSA sound driver which is now in svn, along with some initial (long overdue) work towards tidying up the audio subsystem.