Started working on engine nodes

test/scripts/child_engine_node.toy

@@ -0,0 +1,14 @@
+var tally: int = 0;
+
+fn onInit() {
+	print "child init called";
+}
+
+fn onStep() {
+	print "child step called";
+	print ++tally;
+}
+
+fn onFree() {
+	print "child free called";
+}

test/scripts/parent_engine_node.toy

@@ -0,0 +1,11 @@
+fn onInit() {
+	print "init called";
+}
+
+fn onStep() {
+	print "step called";
+}
+
+fn onFree() {
+	print "free called";
+}