MySQL Sandbox 3.0.19 supports more binary tarballs

Written for MySQL Sandbox by Giuseppe Maxia on 2011-10-09

MySQL Sandbox 3.0.19 now supports tarballs that don't start with 'mysql'.
Supported prefixes are 'mysql', 'percona', and 'mariadb'.
You can also add a prefix to the extracted tarball directory.
These changes have the side effect of making "make_sandbox" backward incompatible. The syntax goes from
"make_sandbox TARBALL [--export_binaries] [options for low_level_make_sandbox]"
to
"make_sandbox [--export_binaries|--add_prefix] TARBALL -- [options for low_level_make_sandbox]"
(notice the '--' before the final options)