ENH: adding generalizedNewtonian to laminar turbulence model

The generalizedNewtonian viscocity models were ported from
the org version and added to the laminar turbulence framework.

This allows use in compressible and incompressible solvers
through the turbulence dictionary under the laminar sub-dictionary.

The thermal laminar viscosity is taken from the thermo for solvers
that use thermo library or from the transportProperties dictionary
for incompressible solvers.

At the moment the option to include viscocity models through the
transportDict is still available.

The icoTabulated equation of state was ported from the org version.

STYLE: use 'model' instead of 'laminarModel' in tutorials