Helloworld

This branch adds top-level 'code' and 'design' directories for code and design files, respectively.  Code directory has pong 'hello world' code in it now.  There are some .gitignore files around that keep empty directories in the repository (see http://stackoverflow.com/questions/115983/how-do-i-add-an-empty-directory-to-a-git-repository).  There's also a top-level .gitattributes file that should make git convert line endings in text files to be appropriate for whatever platform they're checked out on (see http://adaptivepatchwork.com/2012/03/01/mind-the-end-of-your-line/).

I built the code on my Mac and it works, just opens the blue "Hello world" window that does nothing.