Only show keys available in selected ensembles

[oysteoh]

In #223 a bug is described where clicking a parameter in a given ensemble raising util_abort.

Ref @rnyb - the parameter is not available for the selected ensemble. I'm not entirely sure why the parameter is available in the select-box when only this ensemble is selected - that needs to be investigated.

We have fixed the issue not to util_abort on us, but we should discuss how to visualize / populate select-box with parameters.

• Should we only show the parameters available across the selected ensembles?
• Should we show all parameters possible and only draw where data is present?