Postprocessing: run conditions

[ashleaRPI]

There should be a function after (not dependent on, call it after) doPostProc that outputs the run conditions that the PDE was solved at as a data file.

Example:
run parameters that were used:
Ma: 0.25 + 1.0e-100im
aoa: 0.03490658503988659 + 0.0im
dt: 0.00039
a_inf: 1.0
rho_inf: 1.0
c: 1.0
mesh.coord_order: 2

opts[stabilization_method]: clipJacFast
opts[output_freq]: 1
opts[use_itermax]: true
opts[itermax]: 3
opts[use_checkpointing]: true
opts[checkpoint_freq]: 5000
opts[ncheckpoints]: 2