[0.8] host, port, etc are reserved for anchor elements; let's avoid them

[nevir]

Ends up causing really funky things to occur if you extend a (such as overwriting the host portion of the linked URL)

Polymer({
  is: 'super-link',
  extends: 'a',
  ready() {
    this.setAttribute('href', '#awesome');
    // When we set `this.host` up the stack, we screw up the href
  },
});

[Punk-UnDeaD]

in Firefox all ok
but Chrome failed

[sorvell]

Fixed in version 0.9