A few tests for script options.
Drop "zpool28fix" flag. Set to "true" by default.

This does not, however, cleanup the logic as a result. Bit wins could
happen with that, but touches a lot of code that will be refactored
later anyways.
Use getopts to parse script options

getopts is POSIX compliant and surprisingly portable; even SVR4 supports it.
Simplify "prefixes" join; avoid sed call.
Convert Note(), Warn(), et al to printf
Remove $zero_seconds. Move calls to where they're used.
Simplify SkipPool logic

Further paving the way to combine both getopts sections
Merge "generic options" and "pool options"
reduce noise in tests
Move getopts test to integration directory