Gravity Perks - Limit Checkboxes 1.3.16

• Added support for showing Checkbox's admin label (if set) in the span limit setting.
• Updated plugin author.

Removed unused method Array.prototype.gplcUnique.

Fixed conflict with Internet Explorer 11
Fixed conflict with Populate Anything where checkbox count was calculated incorrectly.
Fixed another potential performance issue.
Fixed a few performance issues when limiting a large number of checkbox fields.