2.3.0

• Improved performance of get_srcset_array
• Added advanced image compression option (available by adding hook to functions.php)
• Duplicate entires now filtered out from srcset array
• Upgrade Picturefill to 2.3.1
• Refactoring plugin JS, including a switch to ajax for updating the srcset value when the image is changed in the editor
• Now using wp_get_attachment_image_attributes filter for post thumbnails
• Readme and other general code typo fixes
• Gallery images will now contain a srcset attribute