Using ATTiny13 with Arduino IDE 1.6

I am planning a project for classes to work on at my school. It has to be very, very low cost, so I've decided to start using the Atmel ATTiny13 chip (~£0.37). I am trying to program it (at home) with the Arduino IDE v1.6, according to this tutorial. However, when I try and copy the 'attiny' folder into the 'hardware' folder, nothing new shows up in the tools>board menu. I'm guessing this is associated with the new board manager, but that wants a URL.

I could revert back to using a different IDE version, but I've just persuaded my school's IT support to install this IDE, and I can't imagine them being too pleased with having to install an older version. Also, the /hardware/ folder will be hidden away on some network drive which I don't have access too, so using the 'Boards Manager' is ideal.

Is it a simple task to create the necessary web page for adding boards from the 'boards.txt' file - is there a tutorial? Does anyone know of a URL for adding the ATTiny13 to the Arduino IDE 1.6? Or of a way of adding it some other way?

Thanks,
Archie

Perhaps this will help:

That worked, except when I tried to load 'blink', my LED stayed solid and didn't flash. I think this might be an issue with the clock speed and delay function not working, but I can't seem to remedy it.

This method also relies on the user having access to the /hardware/ folder, which I'm not sure I will. It would be great to be able to use the boards manager.