worked on function call return type check and started checking return type

tests/sprint3/test/sp3_multiple_args.alpha

@@ -0,0 +1,17 @@
+type rec: [character: x; integer: y]
+
+type T2: rec -> integer
+
+type main: string -> integer
+function entry: main
+function bar: T2
+
+bar2 (r,s) := {
+    return r;
+}
+
+entry (arg) := {
+ 	[ integer: result ; rec: w]
+ 	result := bar('c', 7);
+	return 0;
+}

tests/sprint3/test/sp3_multiple_args.alpha~

@@ -0,0 +1,17 @@
+type rec: [character: x; integer: y]
+
+type T2: rec -> integer
+
+type main: string -> integer
+function entry: main
+function bar: T2
+
+bar2 (r,s) := {
+    return s;
+}
+
+entry (arg) := {
+ 	[ integer: result ; rec: w]
+ 	result := bar('c', 7);
+	return 0;
+}