Image_CAPTCHA proposal updated

Hi devs, well, in the last few days I found out that being on the road quite a lot, changing the mail client and having a provider with crap webmail access is quite a killer combination. So this explains my absence to this list despite the pear-qa voting process. Sorry for that. More importantly, however, I updated the code for Image_CAPTCHA and now again would like to hear your feedback before I start the CfV. This is what I have changed: * Now I am using Image_Text. I have to admit that I still have to learn more about the optimal usage of this class, however I think I will be able to sort this out with Toby. * I implemented Philippe's suggestion to let the user define the phrase. * I also changed the constructor a bit: the user now can provide the prase and also font options for Image_Text The new code and demo are online, please have a look :) Thanks, Christian