Added automatic backtracing via RegisterStacktrace in Backtrace. Added a simple hello world demo that just throws up a window. Started working on TileSet again and skeletoned a demo for it.

demo/backtrace/cpp/demo.cpp

@@ -0,0 +1,28 @@
+/*
+ * This demo starts up and intentionally crashes itself to prove the backtrace stuff works
+ */
+
+#include <libsdlgame/libsdlgame.h>
+
+class Object {
+private:
+        int *x;
+public:
+        int crashme(void);
+};
+
+int Object::crashme(void)
+{
+        this->x = 0;
+        return *(this->x);
+}
+
+int main(int argc, char *argv[])
+{
+  RegisterStacktrace();
+
+  // We don't initialize anything here because we would lose the memory
+  Object x;
+  x.crashme();
+  return 0;
+}