Add objdiff setup

This is intended more as a proof of concept as we figure things out
than the start of an actual decompilation in this repository.  Target
object files are currently "bring your own."

src/Jet2.cpp

@@ -1,17 +0,0 @@
-#include "Core.hpp"
-
-
-// Address: 0x0022FCE0
-// Core.cpp really seems like a more natural place to put this, but it doesn't
-// appear to be with Core.cpp's other data in .data
-Game * g_game;
-
-
-// Address: 0x0006F9E0
-// Matching: yes
-void main(void) {
-    g_game = new Game(NULL, 0);
-    g_game->initExecRootObj();
-    g_game->mainLoop();
-    delete g_game;
-}