interpolate (interpData()) for all timesteps and make available to other functions.

[andrejadd]

Functions that need interpData() output are

• getPlumeStats()
• plotSpatialImage_main()

Note: This concerns in particular function makeSpatialAnimation(). Maybe there is a way around or keep it as it is for now.

[andrejadd]

predicting does actually not take so much time (e.g. for the Comprehensive Data set) as anticipated. So this has a low priority.