Add jf-assembler executable

This service reconstructs the various modules and sends out a
image metadata stream for further consumers.

jf-assembler/test/main.cpp

@@ -0,0 +1,8 @@
+#include "gtest/gtest.h"
+
+using namespace std;
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}