Add empty_blog subcommand to core
Remove some old code [closes #406]
Remove empty_options flag
Use WP_CLI\Iterators\Query instead of ->get_col
Fix post type argument in comments
Change empty_terms and empty_comments to keep_terms and keep_comments
Moving empty blog subcommand to blog command
Move empty blog subcommand to blog command; create separate class for multi-site commands so that we can make blog available to single site installations
Rename wp blog truncate to wp blog empty
Remove empty subcommands args; move empty terms/taxes, posts, and comments; insert default terms/taxes
Update man pages
Rename multisite.feature to blog.feature; add feature tests for wp blog empty
Add docblock mention for --yes flag
Merge pull request #410 from tlovett1/feature/blog-empty

Empty blog subcommand