vieet: list the sections of an eet file if a section isn't passed.

Thanks to Sachiel for suggesting this feature.

src/bin/eet/vieet

@@ -14,9 +14,17 @@ die() {
 }
 
 usage() {
-    die "Usage: vieet <eet file> <section>"
+    die "Usage: vieet <eet file> [section]"
 }
 
+EETFILE="$1"
+SECTION="$2"
+
+if [ $# -eq 1 ]; then
+    eet -l "$EETFILE"
+    exit $?
+fi
+
 if [ $# -ne 2 ]; then
     usage
 fi
@@ -25,8 +33,6 @@ if [ -z "$EDITOR" ]; then
     die "EDITOR env var must be set."
 fi
 
-EETFILE="$1"
-SECTION="$2"
 TFILE=$(mktemp)
 
 if [ $? -ne 0 ]; then