standalone: Add explicit -- for delimiting run args vs NAC3 args

nac3standalone/demo/run_demo.sh

@@ -10,6 +10,10 @@ fi
 declare -a nac3args
 while [ $# -ge 1 ]; do
   case "$1" in
+    --help)
+      echo "Usage: run_demo.sh [--help] [--out OUTFILE] [--lli] [--debug] -- [NAC3ARGS...]"
+      exit
+      ;;
     --out)
       shift
       outfile="$1"
@@ -20,13 +24,22 @@ while [ $# -ge 1 ]; do
     --debug)
       debug=1
       ;;
+    --)
+      shift
+      break
+      ;;
     *)
-      nac3args+=("$1")
+      break
       ;;
   esac
   shift
 done
 
+while [ $# -ge 1 ]; do
+  nac3args+=("$1")
+  shift
+done
+
 if [ -n "$debug" ] && [ -e ../../target/debug/nac3standalone ]; then
     nac3standalone=../../target/debug/nac3standalone
 elif [ -e ../../target/release/nac3standalone ]; then