move run_command() back into the WP_CLI class
add 'color' config option. fixes #267
'color', not 'colors'. see #267
add --config global parameter. fixes #272
fix path to wp-cli.yml. see #267
add --debug global param. fixes #177
merge back run() method into after_wp_load()

not needed and avoids confusion with run_command()
replace WP_ROOT with ABSPATH
add config spec
add tests for --quiet flag and don't suppress output on fatal error
replace WP_CLI_QUIET with WP_CLI::get_config('quiet')
make use of defaults
move special args handling to separate class
rename bootstrap() to load_depdencies()
introduce WP_CLI\Runner class

It contains all the logic related to argument handling and WP loading.
move even more code from utils.php into WP_CLI\Runner
storing the config spec in a static variable is not needed

get_config_spec() is only called once per instantiation, or at most 2
times.
add --param-dump
Merge pull request #277 from wp-cli/config-spec

Better organization of config/runtime keys
support --color and --no-color special args. closes #267