support for port and socket configurations with wp core config
Make wp rewrite (flush|structure) generate .htaccess files properly for apache.
make WP_CLI::add_command() work when called from a Composer package's autoloaded file
instantiate WP_CLI::$root on-demand
introduce get_root_command() getter
convert $root from class static to method static

This avoids accidental direct access from other class methods.
Merge pull request #571 from wp-cli/commands-in-packages

Enable commands to be defined in Composer packages
convert from WP_CLI:: to self::
introduce get_configurator() getter

We don't want to allow people to change the configurator instance just yet.
introduce WP_CLI::get_runner() getter

We don't want to allow people to change the runner instance either.
travis: test against PHP 5.5
bool -> list
remove debug line
Support for `count` as a format type; update PHPdoc
Fix maths error
Scratch, fbc4792 was because I dropped the CSV heading. Update the rest of the scenarios
Update user behat tests to use `--format=count`
Merge pull request #562 from eugeneware/socket_support

support for port and socket configurations with wp core config
Merge pull request #559 from wp-cli/format-count-559

Add --format=count to `list` subcommands
instantiate WP_CLI\Runner on demand; see #571

This allows early commands to be defined in third-party packages.