Included time inside trans_id

Including the time inside the trans_id can be very useful for knowing
which logs to scan. I made this so the trans_id will still be the
same length (the randomness of the remaining uuid4 should be enough
for this use). I also added a convenience function for retreiving the
time information from a trans_id.

If you're wondering why I just didn't use uuid1 that embeds the time,
it's because it also embeds uuid.getnode() which "The first time this
runs, it may launch a separate program, which could be quite slow."
We could supply our own getnode value, but then we have to guarantee
its uniqueness, yada yada yada.

Change-Id: Ie33caf1e839fd1a21b01a928a8b301126bef7396
Merge "Included time inside trans_id"