improved and fixed --list command, original patches by @ib (#772)

accepts all skippable frame identifiers.
display in MB or KB, depending on frame size.
fixed combination of skippable and zstd frames.
diff --git a/NEWS b/NEWS
index b3c2613..641551d 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,7 @@
 v1.3.1
 perf: substantially decreased memory usage in Multi-threading mode, thanks to reports by Tino Reichardt
 perf: Multi-threading supports up to 256 threads. Cap at 256 when more are requested (#760)
+cli : improved and fixed --list command, by @ib (#772)
 build: fix Visual compilation for non x86/x64 targets, reported by Greg Slazinski (#718)
 API exp : breaking change : ZSTD_getframeHeader() provides more information
 API exp : breaking change : pinned down values of error codes