A Beginner's Simple Encryption Tutorial / Example

Encrypts and Decrypts a file. This is not an "uncrackable" type of encryption but once you can understand the basics of this type of file encryption you CAN make better ones than me. This is just a quick example of basic encryption. Highly commented to help beginners. There aren't many good examples on PSC, maybe this one is :), to me, comments are more useful than votes. simple Encrypt / Decrypt.