Merge pull request #279 from bitovi/minor

Move minor into master in preparation for a release
0.4.0
Fix steal.dev.log and steal.dev.warn.

- Remove dev.logLevel
- Set default logLevel to 0 in System config
- Get logLevel by passing the key to steal.config, executing
  steal.config with no params throws.

Closes #220.
Merge pull request #280 from bitovi/fix-log-warn

Fix steal.dev.log and steal.dev.warn.
Add support for lessOptions.
Fix less options test.
Add Promise and System to jshint globals.

Sublime text won't stop complaining about that.
Use a flat object to set less options.

This change removes lessOptions.parse and lessOptions.eval. Thanks to
@stevenchacon for pointing out that we don't need to separate those
options, yay!
Fix test after rebase.
Document System.config.lessOptions.