Added remove_from_resize method

Added the ability to remove an image from the resizable_images array.  Allows for temporarily disabling the re-rendering of the image on window resize.  To re-enable, simply call `run()` and the image will be placed back in the array.

I thought about performing a check on the `src` attribute inside `resizable_update()`, but that only handles the case when the `src` has been changed.  Sometimes I just want to stop it from rendering regardless of any changes made to the element.