A Polymer 1.0 element for image cropping and uploading.
The cropping is based on iCropper [https://github.com/supnate/icropper] by Supnate. It is modified to handle touch events.
Parameters:
- urlUpload
- authToken: optional authentication token (jws) for the header
<img-crop upload-url='[[uploadUrl]]' auth-token='[[authdata.token]]'></img-crop>
