fix forward delete key on snow leopard for irb

Open Terminal preferences, Keyboard tab and then press the 'Edit' button for Key "forward delete" and press CTRL+d, which will display \004

Before, I had \033[3~

Now , pressing "delete" in irb should stop printing these annoying ~~~~~~ chars and actually do the job !!!

This has cost me 1hour of unsuccessful googling, the page which gave me the answer: