Add support for a reference stable vector.

[bbernhar]

Adds StableList, a new container type that holds any type of data contiguously when removal mostly occurs at the end.

[bbernhar]

@bjjones FYI. This is a STL-compatible container-only approach to storing linked-data contiguously (was looking to use it for non-residency cases). It's a similar idea to yours but keeps the container separate from allocation (like the STL), so we can swap them out independently.

[bbernhar]

@bjjones Any concerns? If not, I plan to merge (will be used for Slab Allocation).

FYI, I made you owner. You can veto any change.

[bjjones]

LGTM

Code seems fine. Doesn't look like erase()'d spots can be reused, which seems like a big drawback - could end up a lot of fragmentation, but I'm guessing you know that.

[bbernhar]

Doesn't look like erase()'d spots can be reused

Depends where they are. At the end, always reused. In the middle, not so. But I can lower the chunk size to limit waste (full chunks are reclaimable) or just discard those chunks. Not sure what approach is better.

[bbernhar]

Thanks!