#1 Various modifications, mainly new option

[Michael Norton]

I added a new option to the preferences dialog that lets you set the alpha of the gradient in the background, in case you prefer a more subtle (or more pronounced) gradient. I also made it so the about and preferences dialogs cannot be resized. Lastly, I added "Credit to flarn2006 for various modifications" to the About box. You can remove said credit, but I'd prefer you didn't.

I uploaded a zipfile containing the modified files (in their respective directories) to Mediafire, since it was more than 256k: http://www.mediafire.com/?8rxqjiizka00zxc