Programmatically upload bokeh js/css to the container

This PR add a simple and isolated script to upload bokeh.[min].js[css] files to Rackspace.
This helps in the release process and BEP-2 has to be modified accordingly after merging.

Propose:
```
cdn.pydata.org/bokeh/dev/bokeh.[version].js
cdn.pydata.org/bokeh/release/bokeh.[version].js
``` 
This PR should also include the necessary updates to the `Resources` class so that Bokeh can actually locate these new files. (The `Resources` class should actually get simpler)