The `tempurl` subcommand's second positional argument is called
`seconds` and has heretofore interpreted as the number of seconds for
which the tempURL should be valid, counting from the moment of running
the command. This is indeed a common, if not the most common,
use-case. But some users, occasionally, might want to generate a tempURL
that expires at some particular ("absolute") time, rather than a
particular amount of time relative to the moment of happening to run the
command. (One might make an analogy to the way in which Swift's expiring
object support supports an `X-Delete-At` header in addition to
`X-Delete-After`—and it's the former that must be regarded as
ontologically prior.) Thus, this commit adds an `--absolute` optional
argument to the `tempurl` subcommand; if present, the `seconds` argument
will be interpreted as a Unix timestamp of when the tempURL should be
expire, rather than a duration for which the tempURL should be valid
starting from "now".

Change-Id: If9ded96f2799800958d5063127f3de812f50ef06

- blacklisted flake8 hacking
- fix against E122 continuation line missing
  indentation or outdented

Closes-bug: #1475516

Change-Id: I708d0a3466a1f85c84e478873e142821ce0774cb
Signed-off-by: Hiroshi Miura <miurahr@nttdata.co.jp>

The current code builds a full object listing before performing either a multiple
download or delete operation (and also shuffles this complete list in the case of
a download). This patch removes the creation of the full object list and adds the
ability to turn off shuffle for files when downloading. Also added is a limit on
the number of list results that can be queued by a single call to service.list
without consuming results (reduces memory overhead for large listings).

Some tests added for service.py download and list.

Change-Id: Ie737cbb7f8b1fa8a79bbb88914730b05aa7f2906

- add usage strings for short option such as '-a' for '--all'
  This add all short options  to usage text.
- add missing --header usage help for download command
- some cometic changes

Closes-bug: #1475511

Change-Id: Ibfecac8764669540fa025787548133a50fa50b10
Signed-off-by: Hiroshi Miura <miurahr@nttdata.co.jp>