Fix issue with replication of child datasets silently failing

As reported by David Samms dsamms@nw-ds.com, when replicating with -r, if replication of one of the child datasets failed, subsequent checks did not occur for that child dataset.

% zap rep -v -r zroot/ROOT

## Replication of zroot/ROOT completed, but replication of zroot/ROOT/default
   failed.

% zap rep -v -r zroot/ROOT

## The local and remote snapshots matched for zroot/ROOT and the snapshots
   for zroot/ROOT/default were not compared, so no errors were reported.

Also, proceed with a warning for untested OSes instead of bailing out.

Correct the reported version with zap -v

0.6.7

Bump version, which should have been done for 0.6.6

Fix subcommand options in the man page

0.6.6

Fix subcommand options.

Create a man page

0.6.5

Fix typo.

Bug fixes and argument simplification

Update to version 0.6.4

- Fix issues with replication.
  - Do not require all '-r dataset' arguments to be listed first.
  - Fix error checking.  If only one argument to 'zap rep' was supplied,
    replication would silently fail.  This required breaking the interface.
    Instead of
    zap rep|replicate [-dLSv] [[-r dataset]... [dataset]... remote_dest]
    the format is now
    zap rep|replicate [-dLSv] [remote_dest [-r] dataset [[-r] dataset]...].

- Fix issue with destroy.
  - In 0.6.3 $zptn was updated to be an extended regular expression, but when a
    host was not supplied as an argument, grep was being called with a basic
    regular expression.

- In 'zap snap', do not require all '-r dataset' arguments to be listed first.

Fix problem calling basic sed with unupported a|b

Fix snapshot time capture, which failed b/c basic sed cannot do a|b

Switch to sed's extended regular expressions.  Because part of the
regular expression was stored in a variable that was also passed to grep, one
call to grep also had to be switched to an extended regular expression.

Add options to control behaviour when a resilver is in progress

0.6.2

Add options to control behaviour when a resilver is in progress.

Fix incorrect replication example in documentation

0.6.1

Fix incorrect replication example in documentation.

Add remote replication support and update command options

0.6.0

Add a warning about the change to the format of zap snapshot names.

Create flags to be verbose and to recursively create snapshots

• Use getops for option handling.
• Create snapshots again when a scrub is in progress.
• Let the -r flag be specified for individual datasets
  • To handle parsing the '-r' flags, the create function was broken off into two
    functions: create_parse() and create(). create() creates one snapshot per call.
• Use upper case for global variables.
• Created helper functions pool_ok and pool_scrub.
• Minor changes to warning messages.
• POSIX sh does not support local, so initialize variables intended to be local
  to a function.