Add some example NWC 1.75 binary files.

Add some example NWC 1.75 binary files.

1.75-1.nwc
  George Job Elvey: St. George's Windsor
  http://www.cyberhymnal.org/htm/c/o/comeytpc.htm
  http://www.cyberhymnal.org/mid/s/t/g/st_georges_windsor.mid
  basic piano tune
1.75-2.nwc
  Frederik Chopin: Fantasie - Impromptu
  http://www.keyboard-creations.co.uk/
	http://t1b.co.uk/keyboard-creations/music/Chopin/fantasie.nwc
  moderately complicated classical piece
1.75-3.nwc
  Angels We Have Heard on High
  http://www.cyberhymnal.org/htm/a/n/angelswe.htm
  http://www.cyberhymnal.org/nwc/a/n/g/Angels%20We%20Have%20Heard%20on%20High.nwc
  lyrics
1.75-4.nwc
  Turlough O'Carolan: Thomas Burke
  http://www.oldmusicproject.com/occ/tunes.html
  http://www.oldmusicproject.com/occ/NWC/013-ThosBurke.nwc
  triplets and grace notes