Rework of the Grunt Closure Linter plugin

**BREAKING CHANGE**

Please see the updated README.md for option changes. 

- Cleaned up Grunt options and moved the converter to the folder /tasks/lib/converter for a feature based folder structure.
- The ctools.js has been replaced by the common.js and commandrunner.js
- Updated dependencies (package.json)
- Some more housekeeping

Have fun :)