iFrame auto height.
Fit iframes height to their contentWindow html element.
Usage
Use $element.copyHeight() to equal the iframe's height to its contents' height.
Use $element.autoHeight() to set a periodical height match check in a specified interval. In case heights don't match, the $element.copyHeight() method will be invoked.
License
MIT License Copyright (c) 2017 Alejandro Montañez