Fix group cutting behavior with CC triggered samples (such as sustain pedals)

[praashie]

While trying out the Salamander Grand Piano, I noticed that the sustain pedal sample was not stopped upon releasing the pedal. The SFZ file does include an opcode for cutting the activation sample:

//======================
//pedalAction

<group> group=1 hikey=-1 lokey=-1 on_locc64=126 on_hicc64=127 off_by=2 volume=-20

<region> sample=samples/pedalD1.flac lorand=0 hirand=0.5
<region> sample=samples/pedalD2.flac lorand=0.5 hirand=1

<group> group=2 hikey=-1 lokey=-1 on_locc64=0 on_hicc64=1 volume=-19

<region> sample=samples/pedalU1.flac lorand=0 hirand=0.5
<region> sample=samples/pedalU2.flac lorand=0.5 hirand=1

This commit fixes this problem.

[paulfd]

Thanks alot for the catch and the patch! I have removed the newline and added a test case.