dynamic html imports hack

dynamichtmlimport.js

// currently polymer only only loads html imports
// on first page load. After the first pass over the document, 
// adding any additional <link> elements will have no effect.

// This adds a link to src, and forces polymer to load it
function load(src, fn) {
  var link = document.createElement('link')
  link.setAttribute('rel', 'import')
  link.setAttribute('href', src)
  document.body.appendChild(link)
  HTMLImports.importer.load(document, function() {
    HTMLImports.parser.parseLink(link)
    // CustomElements polyfill needs to process the dynamic imports for definitions.
    CustomElements.parser.parse(link.import.content)
    fn(null, link.import.content)
  })
}

Added "CustomElements parsing" call courtesy of @wkruse https://gist.github.com/wkruse/7481517