Gravity Perks - Limit Submissions 1.1.20

Fixed an issue where the Embed URL rule would not limit entries for URLs exceeding 200 characters in length.
Updated require call to use plugin_dir_path().

Updated references to String.prototype.format() to use String.prototype.gformFormat() as the former will be removed in Gravity Forms 2.8.
Fixed a potential memory leak which could cause PHP fatal errors.

Updated GPLS rules to use admin labels for fields if present.