<core-style ref=...> tags are never deallocated

[david-saslawsky]

The core-style consumers are added in global refMap but are never removed. Looks like a function to undo registerRef() is missing in detached

unregisterRef: function() {
    var idx = this.refMap[this.ref].indexOf(this);
    if(idx >= 0)
        this.refMap[this.ref].splice(idx, 1);
}

This is an issue because this prevents all the template instances of elements using core-style from being deallocated.

[Kinetic915]

I have encountered this same issue as well, with its resulting memory leak.