This function provides a way to request the size of an previously
allocated block. It is useful to to ease the implementation of realloc
functionality based on Allocator_avl.
This patch reflects eventual allocation errors in a more specific way to
the caller of 'alloc_aligned', in particular out-of-metadata and
out-of-memory are considered as different conditions.
Related to issue #526.
With this patch an error message gets printed in
'Allocator_avl_base::free()' if the given address is not the start address
of the allocated block.
Fixes#459.
