Break out track and disc routines. (Disc needs more work)

Add more convenience track routines.
Set access-mode for image routines to be the image drivers - for uniformity.
Some name regularization.
And we're in 2005 now.

include/cdio/types.h

@@ -1,5 +1,5 @@
 /*
-    $Id: types.h,v 1.24 2004/12/18 17:29:32 rocky Exp $
+    $Id: types.h,v 1.25 2005/01/04 04:33:36 rocky Exp $
 
     Copyright (C) 2000 Herbert Valerio Riedel <hvr@gnu.org>
     Copyright (C) 2002, 2003, 2004 Rocky Bernstein <rocky@panix.com>
@@ -221,11 +221,6 @@ extern "C" {
   /*! The type of a track number 0..99. */
   typedef uint8_t track_t;
   
-  /*! 
-    Constant for invalid track number
-  */
-#define CDIO_INVALID_TRACK   0xFF
-  
   /*! The type of a session number 0..99. */
   typedef uint8_t session_t;