Created by: ianw
As a follow-on to 9928144d, update the collapse example with another demonstration of using a link to control the region. This specifically calls-out the href v data-target arguments and also shows the default-expanded example just for reference.
With this the page is getting a bit long, so cut down the lorem ipsum text from the accordian sample html (not the live example; where the full text is left to pad it out).
Also remove the now obsolete note on using a single button and add a note on the prevention of default-action to the usage section.