Removed parameter show_V_flow, removed computation of V_flow, and changed the parameter useConstantDensity to useDefaultProperties

This commit correct incorrect Modelica syntax because conditional
variables are only allowed to be used in a connect statement.
Corrected inproper use of constrainedby if the model is declared as an array of models.
Corrected Modelica syntax, as conditional parameter are not allowed.
Improved weather data reader in searching for the weather file.
Simplified computations
Implemented soil properties using a record.
Simplified YorkCalc implementation and corrected invalid Modelica syntax.
Corrected assignment of soil properties to avoid an error when checking the model in pedantic mode.
Corrected invalid syntax.
Corrected invalid Modelica syntax.
Removed old comment.
Corrected use of conditional connector
Removed conditional declaration of <code>mDry</code> as the use of a conditional
parameter in an instance declaration is not correct Modelica syntax.
Removed incorrect call to <code>Modelica.Utilities.Files.exist</code>
Changed icons and code layout.
Added show_T to examples to plot port temperatures.
Set show_T=true for all cooling tower examples as the state at the ports is plotted.
Revised reference results due to a change in density computation.
Revised reference results due to a change in density computation.
Reimplemented computation of port states to avoid using conditionally removed variable.