Convert to Glyphicons font and move to separate repository.
Convert to Glyphicons v1.7 @font-face and drop the old PNGs.
Change required base class and prefix.
Instead of using an attribute selector, like [class^="glyphicon-"], we now require a base class, .glyphicon.
This improves general performance for larger pages while also increasing the durability of our code (as it doesn't enforce a specific order of classes).
This is in addition to the prefix class (which has also been udpated).
All classes start with .glyphicon- instead of .icon- for a more unique class and consistency with the newly required base class.

See https://github.com/twbs/bootstrap/pull/6342