initialization code

likely the allocation will need to move again at the next checkpoint (we
pass the node height for this value). The new heat zone allocation
strategy uses the heat value to put nonleaf nodes towards the end of the
file and leaf nodes towards the beginning.

- Failure to handle multiple allocators at once (oops)
- Failure to handle a clean shutdown where allocators are destroyed by
  the trace gracefully and so we can't get stats for them after the run
  (need to clean this up eventually)
- Added line numbers to error messages so debugging is easier

allocator trace gets written to

now by src/tests/stress_test7.cc

particular value for the first byte of a key means it may be compared
with memcmp and a length check.

FT-50 Implement toku_builtin_cmp_fun with memcmp and a length check

allocator.

file.

the one and only strategy so far - first fit.

FT-295 Move ybt.h to utils/dbt.h

its own header

FT-296 Move bytestring class to utils/

descriptor/ft_compare_func pair