model+apps+utils+examples+ci+docs: Update code for changes in ns-2.23

- Replace removed RandomVariable with RandomVariableStream
- Replace deprecated usages of AddTraceSource
- Update changed LogComponent interface

ci: This commit also integrates a script for Jenkins and Travis CI to
clone NS-3 and pybindgen repositories, so the code can be built.

docs: Update to reflect new home of ndnSIM and related sources

Change-Id: Ic14e1269bf15366b0041fd670c577053b6704dc7
Refs: #3122, #3123
diff --git a/apps/ndn-consumer-zipf-mandelbrot.hpp b/apps/ndn-consumer-zipf-mandelbrot.hpp
index d0cd4f1..f973240 100644
--- a/apps/ndn-consumer-zipf-mandelbrot.hpp
+++ b/apps/ndn-consumer-zipf-mandelbrot.hpp
@@ -35,7 +35,7 @@
 #include "ns3/string.h"
 #include "ns3/uinteger.h"
 #include "ns3/double.h"
-#include "ns3/random-variable.h"
+#include "ns3/random-variable-stream.h"
 
 namespace ns3 {
 namespace ndn {
@@ -95,7 +95,7 @@
   double m_s;                 // s in (k+q)^s
   std::vector<double> m_Pcum; // cumulative probability
 
-  UniformVariable m_SeqRng; // RNG
+  Ptr<UniformRandomVariable> m_seqRng; // RNG
 };
 
 } /* namespace ndn */