Callback on drop feature + performance + housekeeping

Hey,

List of included features:

1. Added package.json
2. Added bower support (removed libs)
3. Added example directory (copied from http://lorenzofox3.github.io/lrDragNDrop/)
4. Added lr-drop-success callback support
5. Performance. Avoid calling of parseRepeater (lr-drag-data)
6. Code clean-up/housekeeping
7. Update Readme with lr-drop-success and lr-drag-data
8. Added .gitignore
9. Created lrDragHelper service for parseRepeater and lrDragSrcDirective for consistency

All you will need now to run/test directive is:

npm install
npm install -g bower
bower install

Tests now can be executed via:

./node_modules/karma/bin/karma start

If you will have any questions please ask.

I would also like to discuss possibility to publish this directive to Bower.

Cheers