dynamic keyframes, textbox rework, andrea ffmpeg.opts, perpetual chkpt undo, lv2 listbox scroll fix, lv2_blacklist update from trebmuh
lv2 rework, sams ffmpeg icons, elision patch
rework undo compression, add shift viewer overwr/copy/clip/splice, fix paste edl assets
multi-line clip note fix
cleanup of hv6 merge, add webm rendering
merge hv v6, rework trace methods
add missing xml closers, add fix for folder bug, add roundoff fixups
Merge CV, ver=5.1; ops/methods from HV, and interface from CV where possible