Dropped AngularJS parts for now.
Initialized the bower package.
Added dependency jQuery.

No need to use some version ~1, cause this
HTML5 drag andr drop support is needed anyway.
Updated license info
Somewhat more readable arg testing.
Dropped testing a data-opts attribute.

This is not mentioned in the documentation, never used in the plugin.
And for no use for me.
Dropped the method support completely for now ...
Some formatting and "use strict;" set.

Need to declare the start_parent and new_parent vars now.
No need to store the items selector for now.

The stored value was used in enable/disable/destroy
methods.
Formatting and some comments
Moved the clearing code to dragend-handler
Further formatting.
Renamed the parent vars