Update README and add contrib dir

contrib/trace/examples/CMakeLists.txt

@@ -0,0 +1,19 @@
+set(base_examples
+    tsn-point2point-netanim
+    tsn-switched-withFRER-netanim
+)
+foreach(
+  example
+  ${base_examples}
+)
+  build_lib_example(
+    NAME ${example}
+    SOURCE_FILES ${example}.cc
+    LIBRARIES_TO_LINK ${libtrace}
+                      ${libcore}
+                      ${libnetwork}
+                      ${libethernet}
+                      ${libtraffic-generator}
+                      ${libtsn}
+  )
+endforeach()