packages.js: use path.join and cleanup
shift,unshift, slice did not fire changed for specific items
Introduction of the ReactiveList, ReactiveArray tweaks, version dump

ReactiveList:
- Initial commit
- Added a extension to the Handlebars each helper
- Added a example in the example folder

ReactiveArray:
- Make it easier to override the class (now using @constructor.wrap and not ReactiveArray.wrap)
- Improved _indexSet, reverse and sort