Started implementation of model without volume.
Removed energyDynamics assignment

For #39
Merged master and reformatted code.

For #39
Merged master

For #39
Added new implementation of heater/cooler.

For #39.
Merged issue39_idealHeaterCooler_noVolume

This is for #39. This version does not generate any state events when m_flow crosses zero. It allows however only steady-state heater/cooler models.