Replace Skin Temperature by Body temperature

Here: https://gitlab.kitware.com/physiology/engine/blob/2.x/engine/c/PulseEngineC.cpp#L249 and here: https://gitlab.kitware.com/physiology/PulseUnityAsset/blob/5207084/Scripts/PulseEngineDriver.cs#L38

Can also be fixed as part of changes in #11