Affixed ScrollSpy hits bottom and then goes wrong
Bootstrap: affix.js v3.1.1

When you scroll to the bottom, the "position" system is set. But it is not "unset" when you scroll back up (unpin).

I fixed the problem by changing:

.   if (this.unpin) this.$element.css('top', '')

...to...

   if (this.unpin) this.$element.css('top', '').css('position', '')

Dunno if this is a good "fix" or a bit of a hack.

(Sorry if this is a duplictate - I am new to github and cant see how to search for similar issues)
