Add bazel support for examples.

The example utilizes native bazel rules (proto_library, cc_proto_library,
java_proto_library, java_lite_proto_library) to show how easy it is to
build protobuf with bazel's native support. It also makes use of well
known types which was not possible until the latest bazel 0.5.4 release
and https://github.com/google/protobuf/pull/3594 .
diff --git a/examples/add_person.cc b/examples/add_person.cc
index 9bec4b3..856e90b 100644
--- a/examples/add_person.cc
+++ b/examples/add_person.cc
@@ -1,11 +1,17 @@
 // See README.txt for information and build instructions.
 
-#include <iostream>
+#include <ctime>
 #include <fstream>
+#include <google/protobuf/util/time_util.h>
+#include <iostream>
 #include <string>
+
 #include "addressbook.pb.h"
+
 using namespace std;
 
+using google::protobuf::util::TimeUtil;
+
 // This function fills in a Person message based on user input.
 void PromptForAddress(tutorial::Person* person) {
   cout << "Enter person ID number: ";
@@ -48,6 +54,7 @@
       cout << "Unknown phone type.  Using default." << endl;
     }
   }
+  *person->mutable_last_updated() = TimeUtil::SecondsToTimestamp(time(NULL));
 }
 
 // Main function:  Reads the entire address book from a file,