Fast and secure transfer tool for 1541 diskimages.

Changes:

- Lower amount of retries in the block search now, unformatted
  disks will now read faster.
- Removed DOS disk initialisation. If no disk is inserted on
  startup, the drive will not bump the head anymore.
- Not found blocks will not be re-read anymore.
- SCPU fix.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                 3331    6332  52.6% -lh5- e298 Sep 22  2001 dtu
[generic]                 2290  174848   1.3% -lh5- da45 Sep 22  2001 dtu-server.d64
[generic]                 1772    2809  63.1% -lh5- 1fb4 Sep 22  2001 dtu-server.prg
[generic]                 1624    3354  48.4% -lh5- 60fc Sep 22  2001 DTU.guide
[generic]                  306     489  62.6% -lh5- 1ba6 Sep 22  2001 DTU.readme
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         5 files    9323  187832   5.0%            Sep 23  2001