Handling of different temperatures, isotopes, pressure, instruments etc

**From workshop 6th May**

User studies:

* User has data with different isotopes. Here to a first approximation may get away with having just one universe from with S(q,w) are calculated for each isotope dataset
* User has data with multiple temperatures. Here run in parallel MD simulations for each of the temperatures but only refine one set of forcefield parameters common to all temperatures
* User has data from different instruments at the same temperature (and pressure). Here should also have the flexibility that can run multiple MD simulations in parallel, some which focus on high energies and some which focus on low energies
* User has dataset measured at different pressure, same user story as with different temperature