Finished middleware impl and made a CallTrace middleware

lib/middleware-common/src/lib.rs

@@ -0,0 +1,9 @@
+pub mod call_trace;
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}