Compressible TGV testcase

[Cherithl]

A brief list of changes is as follows:

• Added a compressible Taylor Green Vortex testcase
• Added an option to set the reference viscosity for the Sutherland's law, so that we can set reference Reynolds number for compressible turbulent test cases
• Implemented matrix-based dissipation (Base Roe+Entropy fix), that can be utilized in conjunction with any two-point flux for the Interfacial as well as subcell fluxes
• Couple of minor bug fixes in the equation of state functions