The 'Initial key' frame contains the musical key in which the sound
starts. It is represented as a string with a maximum length of three
characters. The ground keys are represented with "A","B","C","D","E",
"F" and "G" and halfkeys represented with "b" and "#". Minor is
represented as "m", e.g. "Dbm" $00. Off key is represented with an
"o" only.
@author Eric Farng
@version $Revision: 1.4 $