Merge pull request #11 from caridy/master

improve yui module detection to avoid executing arbitrary code
adding custom options to control the configuration of shifter per plugin instance, e.g.: lint, coverage, silence and quiet
dumping version 0.4.3
adding some debug statements
adding a utility helper to detect debug mode
removing console.log statement
Merge pull request #12 from caridy/verbose

shifter debug info controlled thru options when creating a plugin
adding apidocs
adding notes about docs