gitiles timestamps lack timezone details

[GoogleCodeExporter]

in this page you can see two timestamps:
https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/2b6e4
89fb5bbab066c8dd55167dc40d790c91bab

but there's no information to indicate what timezones those are in.  the 
reasonable thing would be to assume they're localized, but we have way too many 
bad systems at Google that blindly output PST or are otherwise local to the 
system/office.  adding the explicit timezone (or the UTC offset) would make the 
output unambiguous & reliable all the time.  all other git viewers i've used 
include this.

issue 5 covered normalizing the timestamps from various sources to one timezone 
which is fine, but the final timezone should not be stripped.  collapsing them 
in the blame output so as to get more content in the output is easy to do, but 
that's still unrelated to displaying the timestamp in the log output (as quoted 
above).

Original issue reported on code.google.com by [email protected] on 14 May 2014 at 7:39