Create two test FMUs that have variable interpolation capabilities

[ghorwin]

Test-FMU 1: room model that takes ventilation load as input and provides room temperature

Test-FMU 2: ventilation load calculation model; takes room temperature and enables/disables ventilation to maintain constant room temperature

Value interpolation should dramatically reduce oscillations observed with the non-interpolating variant.

Tricky part is the computation of the Taylor-Series from some arbitrary evolution of a variable within the communication interval.