Update PyNE website based on current `develop`

[gonuke]

The PyNE website has not been updated since 3/1/2018. We should push an update and document the best way to do this, perhaps using a docker image. The CNERG website may provide guidance for this.

Alternatively, we can implement a system that automatically updates the website on each new merge.... doctr?

[gonuke]

Thanks for updating the website @bam241