revloop: A reverse-looper based delay.

*UPDATED to v2!*

This patch takes the incoming signal and routes it into a looper. The looper is set to reverse and record/playback mode is toggled by a shared LFO.

The reversed, delayed loop signal is then passed through a `delay w/ mod` module.

Both wet and dry signals are passed into a stereo `mixer` module and an additional LFO is set to pan the delayed signal back and forth across the stereo spectrum while the dry signal stays centered.

## Changes in v2:

* The patch now starts with recording and playback properly enabled for instant use
* A number of parameters have been starred including “RATE” which controls the overall cycle time for recording vs. playback
* The delay has been set to 100% wet by default, which gives a bit more separation to the two sounds
* The delay type has been changed to `bbd` to help give separate sonic space to the dry and wet signals
* The level of the wet signal is now a starred parameter and has been lowered by default to give slightly more prominence to the dry signal
* Thanks to chmjacques for feedback on the patch UX.

## Changes in v1:
* Initial revision
* NOTE: v1 of the patch starts out with `record` and `reverse` in the wrong states, so you need to tap them on the device to get the patch started. Fix coming soon.

## Developer’s Notes

* Because the state of the record (and playback) buttons on the looper is preserved at save time, this is a tricky patch to save such that it starts up “running”. :)
* There doesn’t seem to be a way to name starred parameters themselves, only the top-level modules. For example, “gain 2” is the wet level on the starred parameters list and can’t be renamed to “wet level”
* My ZOIA sometimes gets stuck in a sort of “caps lock” mode, so the “RATE” parameter is all caps. Fortunately it’s also an important parameter. :)