Now with saner class names.

This change will not work with Bootstrap.

Examples of new behavior:

<i class="icon address-book"></i>  Address book icon

<i class="icon alt addres-book"></i> Alternate color address book icon

<a class="hinvert"><i class="icon address-book"></i></a> icon that
inverts color when then parent is hovered over.

<a class="hinvert"><i class="icon white address-book"></i></a> Alternate
color icon that inverts color when then parent is hovered over.