Differences between Bonnie++ 1.00 and 2.00.

Version 2.00 is totally threaded, this has many subtle impacts on the way the
code works.  This changed the per-char results so I decided to make it do
per-byte tests using write() and read() instead.  The results are now much
less.  From 1.92.

When closing files for the IO tests the operation is to fsync() each file
handle.  This means on Linux and other OSs that agressively cache writes the
write performance will be noticably less, but the results will be more
accurate.  From 1.90b.

The number of seek processes is now 5 instead of 3.  Now almost all new hard
drives have some sort of seek reordering capability, and OSs are getting
smarter about maintaining queues.  This and the increasing popularity of RAID
arrays requires more seek procs to do a reasonable test.
