structure problem
add Boiler_validation_a60.mo for benchmarking.
minor change of IdealRadiatorHeating.mo
Merge branch 'Annex60' of https://github.com/open-ideas/IDEAS into Annex60

Conflicts:
	IDEAS/Buildings/Components/Zone.mo
remove unnecessary parameters and restructure HeatingSystem.mo
adapt IdealRadiatorHeating.mo to be compatible with HeatingSystem.mo. Still bug in Examples/IdealRadiatorHeating.mo.
adapt IDEAS/HeatingSystems/IdealEmbeddedHeating.mo -> not finish.
rewrite IdealRadiatorHeating.mo to use the new Intefaces/BaseClasses/HeatingSystem and update its example.
conversion of IdealEmbeddedHeating and its example
add units and display units to the temperature sensors of the interfaces.
remove Hyst_NoEvent.mo as all its added value has been added to Hyst_NoEvent_Var.mo
add assert statement to HeatSource_CondensingGasBurner.mo to ensure that the set point temperature is within the power map to avoid extrapolation.
use a maximum function to avoid negative mass flow rate in HeatSource_CondensingGasBurner.mo
add a test for the Boiler.mo
update Heating_Radiators.mo and its example.
create Partial_heating_noSTS.mo to avoid code duplication between HeatingSystems/Heating_Embedded.mo and HeatingSystems/Heating_Radiators.mo
work on conversion of HeatingSystems/Heating_Embedded.mo
add Interface for HeatExchanger/emission to get drop down menu with replaceable.
working versionof HeatingSystems/Examples/Heating_Radiators.mo using Partial_heating_noSTS.mo with replaceable emission system.
working version of Heating_Embedded.mo and Heating_Radiators.mo with tuned examples.
clean up code for DHW_ProfileReader.mo and its extension.
change m_flow_nominal to m_flow_nominal_HX to specify that the mass flow rate refer to the HX of the storage tank and not the tapping.