don't load cli/cli.php utilities (unused)
Revert "don't load cli/cli.php utilities (unused)"

It's used internally by cli\Table.

This reverts commit e46e6ec9d7af558580f77091316079f4c534c74a.
behat: set up WP file cache only once, before suite

Also, use run_check() to catch download errors. see #441
define WP_DEBUG in Utils\wp_debug_mode()
never display PHP errors on STDOUT
Merge pull request #443 from wp-cli/refactor-debug-mode

Refactor debug mode
Merge pull request #442 from tolgap/master

Implement list command for theme and plugin