I hope the creator of the icons is not upset by my forwardness, but I've converted these icons to bootstrap style icons for easy use. Visit https://github.com/chrismarlow9/Batch-Bootstrap-Plugin for the project.

It allows you to add the icons with pure CSS style (using rowXcolumn) class name. The CSS file isn't exactly small but I did this for the purposes of people making friendly names for icons and expanding on the project (I tried myself but I hate coming up with semantics for technical things. Anyways, enjoy. I simply used GIMP to Greyscale the image and invert the color to white. Transparent the image on your own (or maybe I will later)...