Solved issue #19 and additional minor change

Issue #19 solved: correct reference of dynamic ventilation
Changed the initialisation of LimPID in AixLib.Utilities:control.PITemp to
be compatible with the new initialisation from
Modelica.Blocks.Continuous.LIMPID
Merge pull request #20 from RWTH-EBC/issue19

Solved issue #19 and additional minor change