Correct taxonomy scaffold code for multiple post types.
Restore accidentally deleted man page.
Remove unnecessary comment.
introduce WP_CLI\Loggers namespace
add back WP_CLI::out(), just to prevent fatal errors
add an EXAMPLES section that features the --post_types parameter
Loggers\Regular: don't expose $handle parameter
keep error_to_string() calls inside WP_CLI

They assume WP is loaded, by calling is_wp_error().
don't use is_wp_error() in error_to_string()

We want to be able to use it without WP being installed.
Merge pull request #470 from wp-cli/loggers

Move logging functionality to separate classes
combine similar custom taxonomy tests
Merge pull request #469 from cyberhobo/tax-scaffold-multiple-cpts

Correct taxonomy scaffold code for multiple post types.
clarify that only the bash code was copied from drush
TableIterator: rename 'limit' parameter to 'chunk_size', so that it's not confused with SQL LIMIT

see https://github.com/wp-cli/wp-cli/commit/b1bd56dd5e2bdc106603c1034affc6a953b5e6b1#commitcomment-3296894