Implement ROC, PR, Cost curves

Vishal volunteered to implement ROC curves on the run pages. I'm opening this issue to keep track of progress, and invite others to join.

The ViperCharts lib is ideal for doing this: http://viper.ijs.si/about/
We had an earlier implementation but this is not supported anymore:
https://github.com/openml/OpenML/blob/master/openml_OS/views/pages/frontend/r/subpage/run.php#L194

One important difference is that previously, we used the ViperCharts API (running in Ljubljana) to generate the plots and then pull them in. This time around, I would run ViperCharts on our server, as this is one dependency less to worry about.

Note: This should ideally be done in a JS-only way: get the data via ElasticSearch and push them to the ViperCharts library, so plots are created on the fly. I want to avoid PHP dependencies since the frontend will very likely be rewritten in Django+React. Just tell me what data you need for generating the plots, and I will add them to ElasticSearch.

Here is an example for doing JS-only plots for datasets:
https://github.com/openml/OpenML/blob/master/openml_OS/views/pages/frontend/d/javascript.php

The current JS for the run page contains a lot of legacy code, which I'll clean up asap:
https://github.com/openml/OpenML/blob/master/openml_OS/views/pages/frontend/r/javascript.php

Start with openml_OS/views/pages/frontend/r/javascript.php and the dataset example in openml_OS/views/pages/frontend/d/javascript.php, then review the earlier run-page implementation. Determine the Elasticsearch data needed for ViperCharts and how to run the library on the server. Done means ROC, PR, and cost curves render on run pages through JavaScript without a PHP dependency.