[keyboard] take advantages of keyboards having more than 60 keys

[allan-simon]

for the moment we only manage 5 octaves (from C2 to B7), if there's a note (both output or input) out of this range, the note is ignored , which may be problematic for some edge cases

[allan-simon]

actually looking to source of original linthesia it seems that the common length of keyboards are

37 , 49 , 61 , 76 and 88 keys