- Fixed a bug where a pool_free() on the most-recently allocated pool

  item was trying to make that memory available to the pool, but it
  failed to adjust the right variable.
- Fixed a bug in pool_free() where the return of the entire live
  extent back to unallocated status did not obey POOL_CLEAR.
- Use the new() and new_array() functions instead of malloc().
- Changed the sqew variable to skew.
- Some other minor formatting tweaks.