terminal: fix up horizontal scan-line characters

terminal: fix up horizontal scan-line characters

The DEC special graphics set defines entries 0x6f to 0x73 to be:
  Horizontal Scan Line 1
  Horizontal Scan Line 3
  Horizontal Scan Line 5
  Horizontal Scan Line 7
  Horizontal Scan Line 9
However, the first Unicode drafts included only Scan-Line 5. Since
Unicode-3.2 the other Scan-Lines were added and are available in most
Unicode fonts now.

The codes are listed here:
  http://www.fileformat.info/info/unicode/block/miscellaneous_technical/images.htm?start=9089
Or more precisely:
  Scan 1: http://www.fileformat.info/info/unicode/char/23ba/index.htm
  Scan 3: http://www.fileformat.info/info/unicode/char/23bb/index.htm
  Scan 7: http://www.fileformat.info/info/unicode/char/23bc/index.htm
  Scan 9: http://www.fileformat.info/info/unicode/char/23bd/index.htm
Scan 5 is kept the same as before as it wasn't added separately and was
already correct before.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>