Delay a random jitter period prior to request a Router ID for REED. (#554)

* Delay a random jitter period prior to request a Router ID for REED.

* Update Cert_5_1_09_REEDAttachConnectivity.py to pass Travis check.

* Add CLI to set/get the ROUTER_SELECTION_JITTER and update Certification scripts.

  - add 'posix-ncp' to allow failure list in .travis.yml.

src/cli/cli.cpp

@@ -120,6 +120,7 @@ const struct Command Interpreter::sCommands[] =
     { "router", &Interpreter::ProcessRouter },
     { "routerdowngradethreshold", &Interpreter::ProcessRouterDowngradeThreshold },
     { "routerrole", &Interpreter::ProcessRouterRole },
+    { "routerselectionjitter", &Interpreter::ProcessRouterSelectionJitter },
     { "routerupgradethreshold", &Interpreter::ProcessRouterUpgradeThreshold },
     { "scan", &Interpreter::ProcessScan },
     { "singleton", &Interpreter::ProcessSingleton },
@@ -1786,6 +1787,25 @@ exit:
     AppendResult(error);
 }
 
+void Interpreter::ProcessRouterSelectionJitter(int argc, char *argv[])
+{
+    ThreadError error = kThreadError_None;
+    long value;
+
+    if (argc == 0)
+    {
+        sServer->OutputFormat("%d\r\n", otGetRouterSelectionJitter());
+    }
+    else
+    {
+        SuccessOrExit(error = ParseLong(argv[0], value));
+        otSetRouterSelectionJitter(static_cast<uint8_t>(value));
+    }
+
+exit:
+    AppendResult(error);
+}
+
 void Interpreter::ProcessRouterUpgradeThreshold(int argc, char *argv[])
 {
     ThreadError error = kThreadError_None;