fiob library prototype.
Some test aren't passed.
Hack for all tests.
Segfaults for Roman.
fio_batch isn't used for snapshot
WAL is written as prior to.
o_direct: review fixes. Remove files committed by mistake.

Remove fiob_open_flags, use "mode" consistently.
Fix errno assignment in fiob_close().
Drop recursive calls. Rewrite by review.
o_direct: review comments

Fix styler
Clarify tricky pieces of the code (at least make them clearer to yours
truly).
Fix a bug with incorrect return value from fwrite() & O_DIRECT.
Merge remote-tracking branch 'origin/stable' into o_direct