Sound ducking release not smooth about mpf-mc

[qcapen]

This bug is caused by comparisons in the code between signed and unsigned integers causing undesired behavior and calculations. To resolve, I am going through all signed/unsigned integer variables and ensuring their consistent use and proper casting when comparisons are necessary. Sample positions/durations are unsigned values while envelope stage positions can be negative therefore are signed. The code did not properly cast variables of mixed types when performing comparison operations.

[qcapen]

Fixed