fix: remove dependency on jQuery

Remove dependencies on jQuery and jQuery-UI and implement own Drag 'n' Resize handler.

Warning: breaking change! The handle option for resize is now an array of handles e.g. ['s', 'w', 'n', 'e'] for corner handles.

A drag handle can be either an element tag e.g. <h2> or a class name e.g. '.my-class'

closes #2