REAPER v6.29rc4

v6.29rc4 - May 11 2021

* Includes feature branch: custom metadata columns in Media Explorer
* Includes feature branch: razor envelope editing
* Includes feature branch: ReaSurroundPan
+ JSFX: effects may now request samplerate for opened media using file_riff(fh,nch='rqsr',srate=desired_samplerate);
+ Super8: allow drag-drop of samples to channels
# ReaSurroundPan: clear automation touch/latch on mouse up [p=2442627]
# ReaSurroundPan: minor control positioning tweaks