#1171 and #1161 fixed (Validity range of dynamic viscosity function for ideal gases).
Replaced dynamic viscosity and thermal conductivity computation by the wider range from MoistAir (which neglects influence of moisture). The range is now 123 .. 1273 K. Outside of this range linear extrapolation is used, so that the error also in a much larger range up to 6000 K is not very large.
This required to introduce a new polynomial evaluate function in Modelica.Media.Incompressible.TableBased.Polynomials_Temp.
Furthermore, a test model was included in ModelicaTest that compares with a pure ideal gas approximation and checks whether the variables can be differentiated.

git-svn-id: https://svn.modelica.org/projects/Modelica/trunk@6760 7ce873d0-865f-4ce7-a662-4bb36ea78beb