Purge Options

Hello! Adding my two cents about the purging options available via scripting.

At this time, it's only possibile to purge single groups via scripting.
A zone-level-purging capability would be very useful, so we won't have to create endless groups just to take advantage of the purging feature. Something simple, like purge_zone(zone_id, 0/1) would be nice and very useful.

Another thing that limits the usage of multichannel audio files, is that we can't purge single channel files. Since multichannel are the most convenient way to work with multi-mic recordings, if there's a way to purge a single channel it would be really cool. But I'm sure that's more difficult to implement, since purging a part of a sample it's going to be a quite complex. Well other cool and easier function would be: "generate groups from multichannel files". So if I have a mapped piano with 4 stereo mic positions, I can generate 4 groups with a stereo position in each one. Upon saving the samples will be split accordingly.