extracting content
http://stackoverflow.com/questions/27610589/access-contents-of-content-within-a-polymer-element
HTML
<link rel="import" href="http://www.polymer-project.org/0.5/components/polymer/polymer.html">
<polymer-element name="my-element">
<template>
<content id="content">Hey</content>
</template>
<script>
Polymer('my-element', {
ready: function() {
alert(this.$.content.getDistributedNodes()[0].data);
}
});
</script>
</polymer-element>
<my-element>Important text</my-element>