Update buffer creation

[ericyd]

• use half of the recording latency as the buffer offset. Not sure why half the reported latency sounds good but it seems to!
• instead of just dropping the part of the audio that would normally be trimmed due to latency, stick it on the end of the buffer. In theory, if the first part of the buffer contained a transient, this might allow the transient to hit at the very end of the loop and "connect" back to the beginning. 🤷🏻 It's a little bit of a shot in the dark, but it didn't seem to harm anything