Support for Polymer 0.5.0

Was playing the past few days with your packages (tx for them) and today they (seemed) were broken since i was creating a new meteor app and receiving errors. After checking polymer.org, i saw they advanced...

So, i have not done a pull request in the past, please be patient with me and reject it if inappropriate.

My plan is to create a working demo including iron:router

Best Regards

Andreas