Fix byte-count data type to match allocators
Fix byte-count data type to match allocators

'int' is no longer a suitable type to track memory usagae, in
a 64-bit world.  Use the 'size_type' from the underlying
allocator, which maps to 'std::size_t' and will have the
appropiate size on all platforms, although also switches from
signed to unsigned.  This resolves a number of warnings
originating in a header file.

che2/bde,che2/bde,bloomberg/bde,bloomberg/bde,che2/bde,bloomberg/bde,bloomberg/bde,che2/bde,bloomberg/bde