Peng-Robinson Equation of State

[huynmela]

Final documentation

[SimonEnsemble]

• comments go above, not below line. e.g. in PengRobinsonGas

• removed official doc string above a, b, kappa etc since it wont be exposed to the user and it wasn't clear what function this was documenting

• put use case in the doc string first line props = calculate_properties(gas, T, P, verbose=true)

• does the CSV.jl package allow comments at the end of the lines? if so, plz put in the sources of your Tc, Pc, omega in PengRobinsonGasProps.csv

:heavy_check_mark: tests pass