Version 0.2.0

This release fixes some issues and adds drag zoom functionality.

Issues Fixed

• Fixed an issue where the page would also scroll during zoom #20 Thanks @courchef
• Fixed an issue where the listener was not properly cleaned up on destroy #19 Thanks @courchef

Enhancements

• Zoom to mouse cursor works. #21 Thanks @lysaght
• Adds drag to zoom functionality. #26 Thanks @pml984