Add basic tool to turn blktrace into fio job file

No documentation yet, it's just a start.

Signed-off-by: Jens Axboe <axboe@fb.com>
Merge branch 'master' of ssh://git.kernel.dk/data/git/fio
btrace2fio: set runtime

Signed-off-by: Jens Axboe <axboe@kernel.dk>
btrace2fio: use percentage_random and add filename option

Signed-off-by: Jens Axboe <axboe@kernel.dk>