adds a few more tasks

doc/TODO.md

@@ -5,3 +5,7 @@ In no specific order, these are the tasks that are outstanding
 * Simple type checking on objects internally. Is that object we're getting out of `msg_eval_arg_at()` actually a block?
 * CMake precompiled header integration. We depend on Clang and to have clang generate a precompiled header, we use the following: `clang -cc1 test.h -emit-pch -o test.h.pch`. Candidates for inclusion include:
 * * branch_prediction.h
+* Garbage Collection — Baker's copying collector or treadmill is preferred for now, will likely move to a different system which includes a one-bit reference counting system once the object persistance and versioning system is in place.
+* Object Persistance - We need to be able to serialize all core types into in-memory versions of themselves, suitable for transmission over a wire. Additionally, this representation should be able to be written to a file.
+* Object Versioning - An object, much like a commit in distributed version control, must have an implicit version increase upon modifications to the structure.
+* Shapes - An object shape is defined as being a hash of the slot names of an object. A shape is like a loose type, and should be an integer. It must be recalculated on any modification to an object that affects the slot table.