v2.1.0

• Switch to an abstract interface for chunk data in the CustomChunkedMatrix classes. This makes it easier to implement custom chunking schemes by making a concrete subclass and reduces binary bloat when multiple schemes need to be compiled. Some templating is still used to provide optional opportunities for devirtualization.
• Check for integer overflow when computing products and resizing containers via the sanisizer library. This involves some changes to the integer types in function signatures, mostly to replace size_t with more appropriate types. We also template the integer inputs in many class constructors so that we can check for overflow when casting to internal types.
• Added a MaxSlabs_ template parameter to SlabCacheStats, to allow callers to configure it with an appropriate integer type.