Remove jQuery dependency

Addresses #7 (jQuery independence) and #17 (vendor prefixes).

DOM helpers added:

    addClass(element, class)
    removeClass(element, class)
    hasClass(element, class)
    classList(element)
    removeElement(element)

CSS helpers added:

    css(element, property, value)
    css(element, properties)

Queue helper added:

    queue(fn) // fn accepts a next callback to continue the queue

Should be a good start, there's bound to be something I've missed.