Allows pass signal arrays to a function

test/circuits/fnarray.circom

@@ -0,0 +1,21 @@
+
+
+
+
+function calc(h) {
+    var res[3];
+    for (var i=0; i<3; i++) res[i] = h[i]*2;
+    return res;
+}
+
+template Test() {
+    signal input in[3];
+    signal output out[3];
+
+    var cout[3]  = calc(in);
+    for (var i=0; i<3; i++) out[i] <-- cout[i];
+
+    for (var i=0; i<3; i++) out[i] === in[i]*2;
+}
+
+component main = Test();