Add C++ Template Code

[buszk]

I implemented a version using the C++ template.

In this version, a llist<int32_t, INT_MIN, INT_MAX> is the lock-free list of int32_t type.

The only caveat I see is the code run ~10x slower. The overhead is due to C++ infrastructure(I guess?), not template or class. I am pretty sure this can be optimized somehow. I am just not very experienced with it.

[buszk]

The performance with cpp-template code isn't bad at all. Must be some problem on my side.