These are more efficient than creating buffers in place when needed.
After replacement discovered that bufNewStr() and BufNewZ() were not being used in the core code so removed them. This required using the macros in tests which is not the usual pattern.
This new implementation should behave exactly like the old Perl code with the exception of updated log messages.
Remove as much of the Perl code as possible without breaking other commands.
This command was previously forked off from the archive-push command which required a bit of artificial option and log manipulation.
A separate command is easier to test and will work on platforms that don't have fork(), e.g. Windows.
