PhpSecureImageGen: Output images with text for CAPTCHA authentication

This is a simple class that generate images with a random text that can be used to perform CAPTCHA authentication, i.e. verify whether a site user is a human or a robot.

The image may be outputted with given text or a random text generated by the class.

The generated image also contains a few random lines to make it for difficult for robots to use character recognition programs to determine what is the text written in the image.

The image is outputted in the GIF format.

The code and the comments in the class are in Portuguese.