Feature request: Add loop mode to samplv1

It may be advantageous to add a parameter to samplv1 to set a loop mode that allows: forward, reverse and alternate. Forward would be normal behaviour like now. reverse would play the loop from end point to start point and alternate would alternate between forwards and reverse. Reverse may seem an odd option but I have seen it elsewhere. Alternate would give a bounce effect that some find useful.

It may be advantageous to allow the quantity of loops to be defined, so that the loop is played that many times and then the tail of the sample is played.