----------------------- AmigaOS 3.2 project --------------------------

Changes for disk.resource 47.1 (8.8.2020):

- To avoid to bring a non existing drive #0 into the
  system a special check for Get/ReadUnitID(0) has been
  added. Previous releases of disk.resource have always
  added drive #0 as DRT_AMIGA if DRT_EMPTY was read as
  unit-id because there exists internal drives which do
  not report their type. Now on DRT_EMPTY on unit #0
  disk.resource checks if the head can be positioned on
  cylinder #0. Only if this succeeds the unit-id is set
  to DRT_AMIGA. The check will be performed only once
  and is flagged via DR_FLAGS.DETECT0.

- To allow the new check to use timer.device the 
  reading of the unit-ids is no longer performed during
  the disk.resource init but is defered to the first
  calls to Get/ReadUnitID(). This will happen normally
  during init of trackdisk.device.

- The id-string of disk.resource is now properly init.