v1.7.0

• Added Sebastian Erb to contributors.
• Added Pace support (min/km) and (min/mile) for Activity Shortcode
• Added Swimpace support (min/100m) for Activity Shortcode
• Added 'image_only' attribute to [activity] and [route] shortcode to optionally remove data table.
• Added boolean filtering to shortcodes to prevent false-positive "truthiness" to a shortcode attribute like image_only="false".
• Removed 'max-width: none' from activity image to make it responsive.