Added TotalFreeEnergy auxkernel for #4413
Added 2 variable test for TotalFreeEnergy for #4413
Added TotalFreeEnergy to examples for #4413
Added missing gold file, a new error check, and updated input file syntax #4413
Merge pull request #4433 from tonkmr/free_energy_auxkernel_4413

Added TotalFreeEnergy auxkernel for #4413