minor bug: misleading text in DavOrgan module

[Hanno <shaftoe nurfuerspam de>]

The text declares the lever as "harmonics". Thats completely wrong and was the 
reason I did not understand the working of that module. I used it completly 
through hearing because the module never did what it should. Cause it's not 
harmonics what you put in, it's the pipe length. And thats totally different.

16th should be 16" and means 16ft pipes which is -1 octave from the basetone. 
8th is the basetone, 4th is 4" the first octave 2" the second and so on. 

By the way it would be nice to have some other pipelength too for this module. 
I described useful pipelength in an earlier comment "how organs work"

Hanno