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/model/cs/ndn-content-store.hpp b/model/cs/ndn-content-store.hpp
index cdbb1ea..36994f8 100644
--- a/model/cs/ndn-content-store.hpp
+++ b/model/cs/ndn-content-store.hpp
@@ -183,6 +183,10 @@
   static inline Ptr<ContentStore>
   GetContentStore(Ptr<Object> node);
 
+public:
+  typedef void (*CacheHitsCallback)(shared_ptr<const Interest>, shared_ptr<const Data>);
+  typedef void (*CacheMissesCallback)(shared_ptr<const Interest>);
+
 protected:
   TracedCallback<shared_ptr<const Interest>,
                  shared_ptr<const Data>> m_cacheHitsTrace; ///< @brief trace of cache hits