This makes it possible to accept that on Linux %w returns "01" instead
of "1", for example.

Also moved %c and %Z out of there, even though they are standard,
because these are locale dependent (and e.g. on Windows and Mac they
return different strings).  Finally, sorted the tables slightly
different, to match my standard docs better (%a before %A).

of day, day of week, and season.

Fix the weekday predictions -- these seemed to be all bogus.  The new
predictions seem to correspond with strftime() on Solaris and IRIX, so
I believe they are correct.

Get rid of the test for non-standard format %C returning "the same as
date(1)".  This is hard to do reliably without opening a pipe to date,
and moreover, on IRIX 6.2, %C yields the Century.  So we use that
instead.  (We don't complain about this in non-verbose mode anyway.)

options.  Also added two: %n and %t (newline and tab character).

don't need the if test for verbosity when checking for results of an
unsupported option.

running verbose.

1. If a conversion isn't supported on the current platform, just
   ignore it, unless running as a script (i.e. verbose)

2. Don't use time.time() and os.popen('date') to get the raw values.
   These will always be different!