Remove dependency on oclock

OS X doesn't support the clock_gettime API. Ideally we would extend
oclock to do the right thing (TM) on OS X. For the meantime, fall back
to gettimeofday.

Signed-off-by: David Scott <dave.scott@citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #9 from djs55/remove-oclock

Remove dependency on oclock