[Patch] Saner ;) per_type defaults

[Benjamin Kosnik]

> seriously, some time ago I noticed the below problem, easy to reproduce:
> if we keep the size of the chunk fixed and scale only max_bytes, it can
> easily happen that the allocator decide to take charge of the allocation
> (i.e., not passed down to new) but cannot really fulfill it. The easiest
> fix seems to me just scaling with sizeof the size of the chunk too (as
> default, of course, other settings may be more suited in specific
> circumstances).

Nice catch. Hopefully that's the last of the per-type default config issues...

> Took also the occasion to wrap a bit ;)

Thanks. This was a bit of a mess! Looks much better now.

This looks great, thanks.

-benjamin